"Boy Meets Girl" with an '80s twist. Practical, private and reasonably priced; requiring little, yet promising all.Summarize your soul in 25-words-or-less, and find love with the proper stranger. Lawyer of artistic soul, 29, 5' 10", 175 lbs., moderately handsome, interested in wine, travel, things intellectual, seeks attractive professional WF 25-32, to share serious music in a serious relationship. Jewish Princess, in mid-life crisis seeking Prince, preferably not disguised as a frog, but will consider credentialed amphibians.

Extraordinary SWM, playful, affectionate, caring, secure, idealistic scientist, European, handsome, athletic, vegetarian, 5' 7" seeks extraordinary SWF, 25 to 40.

Ads like these published in the back of Washingtonian magazine, are an increasingly popular singles meeting place. "Singles ads" jumped from just two in a 1975 issue, to a full page in 1978, to four pages in this April's edition.

"At first I thought they'd all be rather kinky people," say Doris Langdon, Washingtonian's classified advertising manager. "But I've taken a complete 180-degree turn on that attitude.

"These are truly sincere people. You get a few kinky ones -- we try to screen those out. Most are professional people, over 30. The number of men and women usually breaks even. The majority are white.

"They prefer to be anonymous -- singles' bars aren't conducive to their level in life. Some are well known, some very conservative. Some have just gotten over divorce or a spouse's death and don't want the rejection you can get in the meet-market scene."

Responses to the ads, Langdon says, run from a handful to dozens -- "It's rare that someone doesn't get any. We get a lot of repeaters placing ads, but some who've bought three ads call and cancel because they can't keep up with all the responses. One man places an ad once a year that takes care of him for the rest of the year."

Poring over the "In Search of . . ." ads and circling promising ones was a favorite pastime for condominium manager Sondi Moore. After several months of just looking, she got up the nerve to answer some.

"I expected some weirdoes," admits Moore, 33, of Georgetown. "But with the exception of an occasional nerd, I met nothing but nice, classy, educated people."

After dating several "advertisers," Moore decided to place her own ad. The week after it appeared, "There were 20 letters in my mailbox. And all those people wanted me -- or at least the me in my ad. I got a total of 50 letters -- and they said December was a slow month."

Moore ran a second ad, several month later, that drew 89 responses. But now an accomplished "ad pro," she sorted them into "no," maybe" and "yes" piles, and called all her "yes" men.

"You chat long enough," she says, "to find out if you're interested in meeting each other. It's not at all unusual to talk for an hour or two. I dated about two dozen men, had some terrific times and was booked solid two weeks in advance."

One of her favorites, she says, was a man who sent her just his business card. "I thought it was tacky," she admits, "but I was intrigued. It turned out he was 41, gorgeous, owned seven banks and took me to the nicest restaurant in town. We still see each other off and on.

"In my opinion, ads are the best way to meet people in this town, with the least amount of hassle and expense." Moore became so enthusiatic that she started teaching an Open University class in ad-writing and launched her own single's ad newsletter, the Complete Circuit.

About 18 people, ranging in age from mid-20s to late-40s, attended Moore's recent class in "SWM seeks SWF."

"I came tonight because I was curious as to what type of people would be into this," said a 27-year-old computer operator. "It seems like a pretty good way of narrowing down the field to find people compatible with you."

"I'm tired of running around the singles' bar scene," said a 30-year-old Virginia man. "I'm looking for some stability, and putting your cards on the table like this seems the smart thing to do."

"I never meet single men in my job," said a 38-year-old pediatrician. "I know about three women who got married through ads, so it seems worth trying."

One couple who had just separated after 19 years of marriage attended together. "We're still good friends," noted one. "And we're both in the same boat -- we need to meet new people ."

After two hours of discussion, advice and sample-ad writing, the class favorite was this one by a 28-year-old marketing specialist: SWM, 1953 Convertible, dark trim, blue lights, overdrive, low mileage, like new, any reasonable offer.

Singles ads are gaining in popularity around the country. At the New York Review of Books -- one of the classiest places to run an ad -- "personal ads are up about 30 percent over 1979," says classified ad manager Kathy Metzger. "We started personal ads in 1969 and they grew dramatically in the mid-'70s, to about 55 per issue. Now we run about 105 per issue."

Why the increase? "There are more single people," says Metzger, who says about one-third of advertisers are from New York and the rest concentrated on the East Coast. "The baby boom is getting divorced. And ads have gotten more acceptable in recent years."

"How else," ask Sandy Feldman, president of a new magazine called Singlesminded, "can you meet new people without going out your own front door?"

Last year two enterprising women started running parties, for anyone who advertises or responds to Washingtonian ads. "It seemed like a good way to get people together," says legal assistant Jane Reynolds. "Anywhere from 150 to 350 people have shown up for them."

Singles ads also have become popular gifts. "I get so frustrated with my friends kvetching around about not meeting anyone," says social worker Carol Weisman, 32, of Silver Spring. "I met my husband on a blind date, so I have lots of faith in this kind of thing."

"I gave them as Christmas presents to about six people," says day-care center owner Audra Stone, 29. "My 60-year-old friend got about 10 responses -- I lied in her ad, though, and said she was in her 50s. She's shy, so I called the men for her.

"I ran one for my ex-husband -- he paid for it. He got one response from a gay man, and several from women. He's now got a serious thing going with one the women who responded. I think the whole ad thing's great."

So do Marvin and Lise Gartenbaum of Fairfax, who met through an ad last April, married in September and are expecting their first child in June.

"I'm from California," notes Lise, a 37-year-old social worker, "and singles ads have been fashionable there for years. Being new to the area at a point when I'd like to settle down and have children, an ad seemed like a good idea.

"I got about 60 responses -- only two or three were married or 'slightly off.' My husband's was like the fourth response in the second batch -- I was sort of sorry he wasn't in the fifth or sixth batch. But I really liked him a lot and didn't date others after him. So I gave some of the letters to my roommates."

Program analyst Marvin Gartenbaum, 47, had responded to ads for about six months before he met Lise. "We liked each other immediately. This kind of dating's so logical -- perfect for someone like me. ia single parent with a 17-year-old daughter."

"It was like a fairy tale," adds Lise Gartenbaum. "Only my prince didn't ride up on a white horse -- he answered my ad."

For the best response from a "singles ad," consultant Sondi Moore suggests: Placing an Ad

Be honest in describing yourself and what you want. "The person's going to find out what you really look like -- so why lie? And you get what you ask for, so be truthful."

Avoid overused, subjective words. "We're all attractive and intelligent, or at least we think so."

Include any unusual hobbies or living requirements. If you've got cats you won't give up, mention that you want a cat lover.

Minimize limitations. The more you set, the fewer responses you're likely to get. "But you probably want to set some requirements, rather than putting 'SWF seeks anybody.'"

Think positive, when describing an attribute some may consider a flaw. For example, an overweight person could say they are "well-rounded" or "Rubenesque."

Make your ad eye-catching. Humor is a good way to make your ad stand out.

Protect yourself. It's worth paying extra for the publication's post office box service. Arrange your first meeting in a public place. Make sure someone knows where you're going and who you're going with.

Assess a respondent by phone first. Ask about their interest, job and hobbies. Get enough information to decide whether you're really interested in meeting the person. Responding to an ad

Make your letter interesting and brief. One page is usually sufficient.

Print or type, if your handwriting is illegible.

Answer only those you feel you can live up to. If you're overweight, don't reply to someone who says they want to meet a slender person. Among local publications, that print "singles ads"

Washingtonian: $1.50 per word, minimum 15 words; $15 for a box number and forwarding service. Published montly, 261-2447.

Singlesminded: $15 for 25 words, $10 for box and forwarding. Quarterly, 656-3005.

Complete Circuit: 50 cents a word, 10 for box and forwarding.Monthly, 298-3171.