If the high cost of clothing has you thinking about finally learning how to sew, or at least brushing up on old skills, this is the season to do it. Clothes have never been as beautiful, or as expensive, and the wide range of fabrics available to the home sewer should make anyone think twice about casually buying a ready-made garment. And if you've been meaning to get out the knitting needles and finally start a sweater, DO IT.

Listed below are some of the sewing classes available in the metropolitan area. There are formal classes, private lessons, small group seminars and workshops for everything from simple sewing techniques to Portuguese rug making. Call the numbers listed for further information and additional classes. UNIVERSITY OF THE DISTRICT OF COLUMBIA'S COOPERATIVE EXTENSION SERVICE 282-7410

Free classes offered in basic sewing. Both morning and evening classes will be offered throughout the area beginning Sept. 6. DANNEMANN FABRICS 5524 Leesburg Pike, Bailey's Cross Roads 671-0660

Morning, evening and Saturday classes in various levels of dressmaking, tailoring and special craft classes. Five, 3-hour sessions from $40 to $50. Classes also available at the Laurel and Arlington locations. DEBBIE HILL 591-7493

Private sewing instruction in the student's home by a certified home economist. Classes are held Tuesday, Thursday and Saturday for the beginning to advanced student. Fee is $15 for 50-minute class. THE FABRIC DEN Smallwood Village Shopping Center, Waldorf 843-8119

Six, 1-hour classes will be given starting Sept. 19 for both beginning and advanced students. Fee for all six classes is $24. STRETCH & SEW 703-938-4741

Four area Stretch & Sew locations are offering a new "Sew A Sensational Wardrobe" course consisting of six, 2-hour lessons (fee, $19.95). GEORGES DE PARIS 1229 G St. NW 737-2134

Men's and women's European tailoring and design classes for beginning, intermediate and advanced sewers. Instruction given in English, French, Spanish, German and Greek. The six-month course is $1,200 for two, 4-hour classes a week, payable at a monthly rate of $200. ADVENTURE THEATRE Glen Echo, Md. 301-320-5331

In cooperation with the National Park Service, Adventure Theatre is offering a course in three sessions titled "Create a Costume." Tuition is $33. Registration deadline is Sept. 19. SOO YOUNG LIM SCHOOL OF FASHION DESIGNING 804 W. Broad St., Falls Church 532-3325

Classes in both custom design and designing and pattern-making. The 10-month Custom Design course includes instruction in pattern-making, designing, fitting, tailoring, clothing construction and professional finishing. Tuition is $55 per month plus a fee for text and materials. An eight-week designing and pattern-making course covers the designing and making of a basic skirt, dress and slacks. Tuition is $110 plus a text fee. KIP'S SUNDAY SEWING 244-5382

Individual instruction, consultation and assistance with all levels of sewing, Sundays, noon-6 p.m. Fee is $10 per person for a single class or $45 per person for a series of five Sundays. Call in the evening for details. ANNAPOLIS FABRICS, INC. 59 Forest Plaza, Annapolis 301-224-4288

A range of courses available,including pants fitting, tailoring, drapery making, textile painting and pattern fitting. Costs range from $15 to $40 with an additional $5 registration fee. Evening and Saturday classes available. WASHINGTON WOMEN'S ARTS CENTER Landsburgh's Cultural Center 420 Seventh St. NW 393-0197

Debra Stern will teach "Fabric Design on Silk," an intensive, one-day workshop on the basic principles of textile design. Fereshteh Klauss will conduct a workshop on feltmaking, including a short lecture with slides on the evolution of feltmaking. UNIVERSITY OF MARYLAND COOPERATIVE EXTENSION SERVICE Montgomery County Office 948-6744

A variety of clothing and sewing classes offered including fusible tailoring, string quilting, pattern alteration, basic sewing update, gourmet sewing (handling fine fabrics and designer techniques) and sewing shortcuts. ANNALEE DESIGNER STUDIO 208 S. Payne St., Alexandria 644-8778

Learn to create your own bridal gown, attendant's gowns and accessories. Saturday classes from 10 a.m. to noon begin Sept. 17. Cost is $40. MARANATHA CREATIONS 14221 Sturtevant Rd., Silver Spring 384-1634

Terry Bork begins her 13th year of classes in basic sewing (Bishop Method), lingerie, holiday fashions and home decorations. Four-, six- and 12-week classes held in Montgomery and Prince George's counties; fees $35 to $54. DEBORAH BOOKER 635-8136

Private lessons for beginning sewers. Students will complete two projects--construction of a garment from a pattern and making a garment from a drafted pattern. SUDAN/PARSONS UNLIMITED 301-253-3771

Kay Nelson Sudan and Jean L. Parsons are offering a series of seminars for the woman or man who wants to create her or his own look and a total approach to successful living. Area workshops include "Professional Pressing" and "Fantastic Fit--The Key to Looking Terrific." BARBARA LIPSCOMB 10700 Bickford Ave., Clinton 245-8452 or 868-0754

Basic Sewing and Basic Sewing II will be offered this fall beginning Sept. 7. Course work includes a field trip to a fabric store, learning basic textiles and making a simple garment. MARYLAND SEWING MACHINE & VACUUM CLEANER CENTER Allentown Mall, Camp Springs 899-7200

A variety of classes offered this fall including portrait stitching, machine trapunto, basic sewing, heirloom sewing, sewing on Ultrasuede, bra making, jeans and monogramming. Morning, evening and Saturday classes; tuition $7 to $70. INIS AND ELENOR BEST Oxon Hill 630-7427

Ten-week course beginning Sept. 22 in basic sewing techniques. Fee, $40. MARYMOUNT COLLEGE 522-5600

Marymount is offering a course in clothing construction, emphasizing basic techniques. Open to beginners, it's given Tuesday and Thursday, 12:30-3 p.m. and 3-5:30 p.m. Another course, draping techniques, is open to more advanced sewers, Monday and Wednesday, 9 a.m.-noon. KATHLEEN STEVENSON 5922 Sherborn La., Springfield 451-1559

Learn to construct a blazer in Kathleen Stevenson's "Tailoring Is Easy" course. Six, 2 1/2-hour session beginning Sept. 21 at 10 a.m. or 7 p.m., $25. Call after Sept. 7 for information. FINE LINEN AND PURPLE 11911 St. Johnsbury Ct., Reston 860-8162

Individual and small group lessons given by Anne Lutz in basic sewing, in addition to workshops on collars, set-in sleeves, skirts, blouses and tailored jackets. NETTIE GRAULICH 5533 Sherrier Place NW 686-9469

Small, private lessons for beginnining, intermediate and advanced sewers. Morning and afternoon classes available two days a week for eight weeks, $56. PRINCE GEORGE'S COMMUNITY COLLEGE 322-0998

A course in making drapes and window treatment will be held at the University Square Apartment's Recreation Building in Greenbelt, Md. Four, 2-hour sessions beginning Oct. 25. Cost is $25 to Prince George's County residents. ETHEL MARTIN 583-7382

Small group sewing classes will be given for beginning and intermediate sewers, with emphasis on pattern alteration and tailoring. Fees are $45 and up. RONA SUBOTNIK 11605 Bedfordshire Ave., Potomac 424-8163

Day and evening classes available in pieced-work, applique' and embellishment techniques applied to the make designer jackets and vests. Basic sewing skills required, $60 fee. GARMENT INSTITUTE OF TECHNOLOGY 574 S. 23rd St., Arlington 521-6909

A variety of courses offered in basic sewing, advanced garment construction technology, fittings and retail alterations management. Fees are tailored to the individual. PORTIA HAMMAN Rte. 3, Box 333, Winchester 703-662-2238

Day and night classes for beginning and advanced students beginning tomorrow. Eight, two-hour classes, $50. TRINITY A.M.E. ZION CHURCH 3505 16th St. NW 328-2388

A five-week workshop on the artistic fundamentals of sewing will be offered Saturdays from 11 a.m. to 1 p.m. beginning Sept. 17. There is a $30 tax-deductible cost. COUTURE FABRICS OF ALEXANDRIA 320 King St., Alexandria 703-548-7709

Sue Tobias will teach a beginning and an advanced class on Ultrasuede techniques beginning Sept. 28 and Oct. 11. TWAIN REVELL 11102 Parkmont Dr., Upper Marlboro 301-627-4276

Learn to sew garments with professional results in your home. No special sewing knowledge necessary. Requests for specific lessons geared to special fabrics such as Ulstrasuede, leather and silk are welcomed. Fee is $20 per hour with special seminars available for groups of five. VERNA INEZ McCAULEY Sibley Plaza Community Room 1140 North Capitol St. NW 682-0840 or 636-5794

Beginner and advanced beginner classes given Tuesdays and Thursdays from 7-9 p.m. Sewing machines provided. Six sessions, $25. G STREET FABRICS 11854 Rockville Pike, Rockville 231-8982

A wide range of classes including basic sewing, tailoring, luxury lingerie, designer dress workshop, pants that fit, patternmaking, Ultrasuede construction and quilting will be offered at G Street's new Rockville location beginning Sept. 24. COOPERATIVE EXTENSION SERVICE AND VOCATIONAL AND ADULT EDUCATION DEPARTMENT 691-3433

The Fairfax County "Stretch the Dollar" program offers free sewing classes for disadvantaged and handicapped persons, as well as for people whose incomes are limited. Classes will be at Groveton High School. ARDIS SCHOOL OF THE ARTS 1728 Connecticut Ave. NW 234-6537

A variety of courses including patternmaking, leather and fur construction, shirtmaking, fashion sewing and French draping and construction. VIRGINIA WHITE 610 Hampton Dr., Oxon Hill 839-4081

Classes for beginners who have never sewed before and intermediates who need help. No required skills. Classes meet once a week, times and days flexible. WASHINGTON FASHION ACADEMY 1333 Holton La., Langley Park 431-3030

Learn to make clothes the professional way with courses in women's and men's fashion design, tailoring, patternmaking and creative design and alterations. Six to 24 class hours a week available; fees vary. FAIRFAX COUNTY PUBLIC SCHOOLS Office of Adult and Community Education 7510 Lisle Ave., Falls Church 893-1090 or 893-1092

Single session classes in sewing for profit, halloween costumes, monogramming and French hand sewing, $6 per session. Extended classes in making silk and Ultrasuede suits offered; fees start at $29. HOOD COLLEGE 301-663-3131

Late registration is still available for a variety of sewing classes, including clothing construction, experimental clothing, basic textiles, family clothing and flat pattern and fitting. KAREN GALLY 13920 Darnestown Rd., Darnestown 948-2255

Sewing workshops for beginning and intermediate sewers to develop construction skills, learn to alter patterns and use your creative skills. Students must bring their own sewing machine. $55 for ten, 2-hour lessons once a week beginning in September and January. MILL FABRICS INC. Pan Am Shopping Center, Fairfax 938-3700

Mill Fabrics' fall classes include beginning and intermediate sewing, tailoring, Ultrasuede, English smocking and quilting. Fees range from $20 to $35. KATHERINE DAVIS/ A WOMAN'S TAILOR 802 Janice Dr., Annapolis 301-268-1843

Katherine Davis will teach three courses this fall. English tailoring, in which the student will construct a blazer or suit ($70 for eight, 1 1/2-hour lessons); couture finishing techniques ($80 for six, 1 1/2-hour lessons); and pattern drafting and apparel design, a course primarily for people who sew well and who wish to learn how to sketch and draft their own patterns ($250 for ten, 2-hour lessons.) A QUALITY COMPANY 6309 Georgia Ave. NW 291-3000

Barbara Whitaker Green teaches day and evening courses in beginning sewing, construction techniques, intermediate sewing, advanced sewing/tailoring and machine embroidery. Classes meet once a week for six weeks, $45 to $50 per course. BISHOP METHOD OF CLOTHING CONSTRUCTION COUNCIL INC. P.O. Box 764 College Park, MD 20740

Classes in basic sewing, shirtmaking, tailoring, dressmaking and fitting will be taught as well as seminars and workshops. Also, a seminar on silk will be given by Mick Thiel on Oct. 6 and 7 at the Ramada Inn at Tysons Corner. Write for further information. MONTGOMERY COUNTY PUBLIC SCHOOLS Department of Adult Education and Summer School 942-8304

A wide selection of sewing classes, including blouse and pants workshops, fitting clinic, pattern drafting, needlepoint, English smocking, and Portuguese rugmaking. Most courses meet for two hours a week for eight weeks; tuition $25. Senior citizens, 65 and over, are admitted free to any course that has at least 10 paying students. Knitting, Crocheting, Needlepoint, Quilting, Crewel and Weaving LIBERTY OF LONDON 3222 M St. NW 338-3711

Fall workshops include beginning smocking, Madeira applique' and Christmas ornaments. Classes meet from 7 to 9 p.m. for four weeks. NANNIE'S ATTIC 1511 Wisconsin Ave. NW 338-3811

Classes and workshops this fall include "Small Projects," where you'll learn piecing, applique' and quilting; quilted vests; double wedding ring workshop; and a Christmas workshop. Classes are open to all levels, including non-sewers who wish to learn quilting. Fees from $15 to $55. CATHEDRAL WINDOW ARTS 703-820-7936

Learn the art of cathedral window quilting with Barbara Watson. Class size is limited to six. No experience is needed--just bring a small pair of scissors and a thimble. Classes Mondays, 1:30 p.m.-3:30 pm. and Saturdays, 1:30 p.m.-3:30 p.m., $8 per lesson. Evening lessons can be arranged. CURRAN SQUARE FABRICS 6725 Curran St., McLean 556-9292

Carol Sondheimer, Maria Gonzalez, Leslie Wood, Jean Parsons and Gail Shinn will lead lectures and seminars on subjects including Ultrasuede techniques and sewing on silk and silklike fabrics. SUSAN LEWIS 13304 Williams Dr., Brandywine 782-4273

Complete a sampler with basic and advanced stitches and a yoke dress during this 6-week beginning smocking class. Groups forming for mid-September start. Cost is $20 plus kit. THREADNEEDLE STREET 4801 Massachusetts Ave. NW 966-1180

Classes in beginning knitting, silk painting for garments, designing knit sweaters, sewing the $500 look and advanced sewing and tailoring techniques for luxury fabrics will be offered. RIMA SHAFFER-MEYER 1303 Geranium St. NW 291-9324

Fiber-artist Rima Shaffer-Meyer is offering two courses: Beginning Spinning for six Saturdays, from 9:30 to 11:30 a.m. beginning Sept. 17. The $120 fee includes materials and use of a spinning wheel during class. Beginning weaving classes meet for 12 Tuesday evenings, 7:30-10 p.m. starting Sept. 13. The $195 fee includes rental of a four-harness table loom and warping materials. OUT OF HAND 208 N. Lee St., Alexandria 549-0939

Morning and evening classes in needlepoint (beginning, intermediate and advanced), canvas designing and smocking (beginning, intermediate and advanced). MARTHA ANN FRY 4212 Bel Pre Rd., Rockville 460-6096

Evening bobbin lacemaking classes wll begin in mid-September. The $60 fee includes eight weeks of instruction (2 hours per week) and supplies. LINDA FOSS 7601 Gifford Ct., Alexandria 922-8830

Beginning and intermediate smocking classes. Four, 2-hour classes with equipment and supplies included for $40. At the intermediate level, learn to design, smock and assemble a little girl's dress. Basic knowledge of smocking and sewing required. MARY PENDERS 703-938-6175

Mary Penders, author of "Quilts in the Classroom--A Guide to Successful Teaching," will offer beginning quiltmaking classes at various locations in the District, Maryland and Virginia. MARY ALICE HEARN 301-946-8358

Weaving and sewing handwoven fabrics will be taught at the beginning and advanced levels. Beginning classes stress weaving techniques with more advanced classes emphasizing design and color. Looms are available to rent. THE YELLOW BINDING 4701 Sangamore Rd., Bethesda 229-1900

"Beginning Knitting" and "Design Your Own Sweater" classes will be start the week of Oct. 17. DIANA PELLETIER Takoma Park 587-8219

Students will learn 20 stitches, make a sampler and design a second sampler using these stitches in Diana Pelletier's beginners' embroidery class. Fee is $25 for eight sessions and includes all materials. In a second course, "Embroidery on Clothing," students will learn how to embroider a skirt, blouse, vest, etc. The $10 fee for two sessions covers embroidery materials. Students should bring the piece of clothing to embroider. Lefthanders are welcome. THE STUDIO/WORKSHOP 4720 Montgomery Ave., Bethesda 654-4453

Small evening and weekend classes or private instruction teaching the "Gentle Arts": Sewing, beginner to advanced 2-hour classes (weekly), $50 per month; private instruction, $10 per hour. Also offering 1 1/2-hour needlework execution and design classes, $40 per month. Stuents of any level accepted. New classes start the beginning of every month. YARNS & TWINES 5008 Connecticut Ave. NW 686-6464

A variety of classes, including beginning knitting, multicolor techniques (Argyle, Fair Isle, etc.), crochet techniques for knitters and finishing hand knits, will be offered beginning Sept. 13. Fees range from $20 to $75 for small classes; private instruction, $10 an hour. THE WEAVING DEPOT 8008 Norfolk Ave., Bethesda 652-7080

Weave your own fabrics for clothing and home furnishings. Beginning and advanced courses offered day or evening on two-harness rigid heddle or four floor looms. Two-harness class, $65 for five weeks (includes $15 yarn) and four-harness class, $95 for eight weeks (includes $25 yarn). Call Sally Stewart for details. THE TAPESTRY ROOM'S QUILT PATCH 3936 Old Lee Highway, Fairfax 273-6937

The Quilt Patch will offer a variety of classes, including basic quilting, machine piecing, Amish quilt, quilted tree skirt and quick baby quilt. Day, evening and Saturday classes available. THE CONTINENTAL QUILTING CONGRESS P.O. Box 561, Vienna, VA 22180 703-938-3246

An intensive three-day event with workshops in quilting, applique' and creative sewing by machine, at Stouffer's National Center Hotel in Arlington Nov. 2-6. Send a self-addressed, stamped evelope to receive information. MINNESOTA FABRICS 301-468-6860

Area Minnesota Fabrics' stores wll be offering quilting workshops, demonstrations, crafts shows and fashion shows this fall. Topics range from shadow quilting to quickie Christmas ideas to energy saving decorating. Call Nancy Angle for more information. SMITHSONIAN RESIDENT ASSOCIATE PROGRAM 357-3030

The Smithsonian's fall needlework courses include instruction on quilting (from start to finish), creative knitting and the basics of colonial rug braiding. Prices vary for members and non-members, with both evening and morning classes available. THE DAHL HOUSE 5323 N. Fifth St., Arlington 243-2781

Choose from a variety of smocking classes (from beginner to intermediate), as well as workshops on Christmas balls, Bishop construction, yoke-making and bonnet making. Materials included in most fees. MARY WASHINGTON BRANCH/ASSOCIATION FOR THE PRESERVATION OF VIRGINIA ANTIQUES Fredericksburg, Va. 703-373-1776

The fifth annual quilt show, Sept. 16, 17, 18 in Fredericksburg, will feature a variety of quilting workshops, including creative piecing, log cabin variations and medallion quilts. For more information and tickets, send a self-addressed stamped envelope to: Visitors Center, 706 Caroline St., Fredericksburg, Va. 22401.