Twenty couples gathered around an indoor swimming pool at a Northwest Washington home near Rock Creek on Friday night to dine on steamship round of beef and sip Italian red wine. Later, they partied some more at the Harambee House hotel, drank champagne and danced away the night.

It could have been an elaborate party of old friends. It actually was an elaborate bid to raise money for Marion Barry's D.C. mayoral campaign.

Each of the people eating beside the pool at the home of architect Robert Lewis Jr. and his wife LaGrande had pitched $50 into Barry's campaign coffers to attend the dinner and dance.

In all, 300 Barry supporters and people curious enough about his candidacy to spend $50 attended 17 dinners Friday in private homes throughout the city and later the dance.

By the time the last sip of the 86 bottles of champagne had been drunk, the Barry campaign had netted about $12,000 and gained several more campaign workers.

The Friday gathering was just the latest example of the widely varying ways that the two chief announced mayoral candidates - Barry and D.C. City Council Chairman Sterling Tucker - are trying to raise money or make themselves better known to prospective voters in the Sept. 12 Democratic primary.

Although the other major candidate expected in the race, incumbent Mayor Walter E. Washington, has not announced his candidacy for reelection to another four-year term, he regularly shows up at events throughout the city, and his supporters staged a mammoth birthday party for him late last month.

In the three months that the campaign has been under way, Tucker has, among other things, danced at Tramps, a Georgetown night club, attended numerous coffees and wine and cheese parties, ridden in motorcades, made countless speeches to community organizations and other groups and promoted his candidacy to prospective donors at a variety of fund raisers.

Barry has campaigned at similar events, but also has had a couple of other less common ways of making money. Washington artist Lou Stovall donated 115 prints of a country scene he painted and the campaign has sold about half of them for $100 apiece.

Meanwhile, Betty King, Barry's special events director, has made an assortment of needlepoint campaign buttons that say such things as "I'm the Marion Kind" and "It's Barry Picking Time."

She has sold them for $5 and $10, reaping about $300 for the campaign so far, and has enough back orders to keep her evenings filled for a while. Still unsold: A $150 needlepoint purse with "Marion Barry for Mayor" inscribed on the side.

"It's a great conversation starter," she said of the needlepoint work, while nonetheless conceding that "there's nothing new in fund raising."

"One of the values of these events (like Friday's dinners) is to provide the opportunity for people to make their donations," she said.

The trick to successful fund raising, according to the local practioners, is to know when and who to invite to which party or event.

"In fund raising you've got to be careful," King said. "You don't want to invite someone to a $100 event when they're good for $250, or they'll say they already gave" when they are invited a second time.

Political fund raisers often list a series of sponsors on the invitation that probably means that they've already paid $50 or $100 to the campaign in connection with that particular event.

King said that people invited to a party often do not know Barry, but they might know one or more of the people listed as sponsors and decide on that basis that the event might be fun to attend.

"Each precinct and constituency is different," she said. Campaign workers "know what is attractive in their area, what will go over."

King said the Barry campaign has held or has scheduled several large citywide fundraising events before June 1 for an important reason: "Frankly, we wanted to try to break loose some of that big money before the rich folks go away for the summer. The poor people stay around."

Although the Barry camp has raised about $70,000 so far, several thousand dollars less than Tucker, it has not been particularly easy, campaign workers say.

"There is soft money and hard money," King says. "Soft money is tax deductible and hard money is political money: you can't take (all of) it off your taxes."

Friday night's campaign event had started out as 40 dinners, but the Barry campaign had trouble getting enough people who were willing to feed a large gathering for free. So there were 17 dinners. The dinner bill at the Lewises, split with two other people amounted to about $300.

Lile Bary, Tucker makes many of his campaign appearances at homes or parties of supporters. Washington lawyers Lou Diamond and Mitchell Cutler, for example are staging a party for Tucker at the Pisces Club on May 23 and inviting 150 of their friends for cocktails.

"They'll meet him and perhaps make a contribution," Diamond said.

Diamond said he and Cutler will be making their Tucker donation when they pick up the $600 to $800 bill at Pisces. CAPTION: Picture 1, Sterling Tucker chats with Gwen Davis, Maria Cebollero and Celeste Crenshaw at Tramps. By Joel Richardson - The Washington Post; Picture 2, Marion Barry dances with his wife, Effi, at his fund raiser. By Gerald Martineau - The Washington Post; Illustration, Needlepoint campaign buttons sell for $5 and $10 to aid Barry's campaign.