FOR THOSE cool summer evenings when there's a breeze or the air conditioning is too chilly, you need a knitted Chanel-type jacket to throw over your shoulders. Now is the time to make one in fluffy mohair, like the favorite made for me by my friend and expert knitting instructor, Ruth Rhone in Michigan.

Ruth first knitted the jacket in soft wook, then edged it with a crochet border cleverly made with silky seam binding. That extra finish made it elegant enough to take it out for the evening. If you make yours like mine in ivory or cream, it's guaranteed to go with absolutely anything in your wardrobe.

Once you've knitted your simple jacket sweater, you can find a soft ribbon for the edging, or use "Ribbon Chic" rayon ribbon. A visit to your local notions department may produce seam binding in just the right shade. The size of your hook will depend on the size of your ribbon, but size B or C is average.

Begin by working into the knitted edge of the sweater to make a foundation row of chain all around. Turn the work to begin working into this first foundation row. Work one chain, then insert hook into third chain from hook. Work one double crochet. Insert hook, going back into previous chain (immediately before the double-crochet stitch), and work one single-crochet into this chain. Then work a second single-crochet into the same stitch. Now work one chain and repeat from the beginning again, working one double-crochet into third chain from hook, etc.

NOTE: Double-crochet is worked as follows:

Work chain edge around sweater, turn work, work one chain. Put thread over hook, insert hook in third chain sticth from hook. Draw thread through (three loops on hook), thread over hook and draw through two loops, thread over hook and draw through two loops.

Single-crochet is worked as follows:

Insert hook in chain, thread over hook and pull through chain. There are now two loops on hook. Thread over hook and pull through both loops.

Q. I've finished my first sweater but I'm really terrified of putting it together. Should I steam it or press it? Will the hot iron shrink the wool? Right now it's lying in the knitting bag -- waiting!

A. Cover your table with a blanket folded in four. Cover that with a sheet. Lay out your knitted pieces and stretch and pin them down on the sheet in the correct shape and size. Cover with a damp cloth and press the iron down on top. Keep pressing and lifting -- never "smooth" the iron along. Allow the pieces to dry (if your sweater is ribbed at the cuffs and hem, unpin them and pull the ribbing into shape while still damp and warm).

When the seater is ready, blocked and dry, unpin the pieces and sew the seams together. To do this, lay the pieces to be joined face-down, edge to edge, lining up the stitches of each side so they fit together exactly. With a blunt needle and matching thread, sew alternately through the head of each stitch, first on one side then on the other.

Does that seem very difficult? Haul those pieces out of your knitting bag right now, stitch them up and get ready to receive compliments at your first wearing.

Q. A couple of months ago, I picked up a package of "sacks" at a garage sale. I thought they would be great for cleaning rugs, but upon examination I found they were 100 percent cotton. I have 18 pieces of 34-inch-by-36-inch unbleached muslin. Have you any needlework ideas?

A. A few years ago I saw a great idea at a New Orleans exhibit: printed grain sack designs with eggs, hens and roosters, and flour sacks with roses and garlands that had been stitched over in bold split-stitch in homespun colors; the whole thing then stretched as a unique wall hanging.

But it sounds as though your sacks are not printed with designs, in which case you could try my idea of "Coloring Book Quilting." Stretch the fabric, trace a simple design (from a child's coloring book, perhaps) and paint it with fabric paints. Now, outline it with stem or buttonhole stitch in cotton floss, take it off the frame and quilt around the design.

You could quickly make a delightful bedspread by joining squares. Made in this way, using your cotton fabric, it will have the look of applique but with none of the work.

A word of warning: Check your fabric for durability by trying to rip a section of it before you begin. It just might be worth spending a few more dollars to buy new fabric of the same type (cotton, unbleached muslin is available). Even with a casual beginning, your end result could turn into a masterpiece, and then you might be sorry you tried putting new wine into old bottles!

Q. I read with interest about transferring photos to needlepoint canvas. I wrote to Judy Roberts, as you suggested, but have had no reply. Can you advise?

A: I can indeed! After many false leads, and finding that Judy Roberts transfers only her own designs to canvas, not photographs, and, in my own frustration, even writing to the chairm,an of the board at Xerox -- help has come at last! Write at once to Needlepoint Portraits, P.O. Box 9, Greens Farms, Conn. 06436. These people will scan your photo with a TV camera linked to a computer and give you a fail-safe graph to be counted on the canvas in sepia tones. The complete kit for a 12-by-12 canvas cost $39.95. Any photo, even an old tintype, can be used. This technique is so interesting and accurate I will write more about it soon. By the bursting mail bags, I know you are all as fascinated as I am.