In a televised debate in the heated Democratic mayoral runoff election of 1973, the 6-foot-1-inch Herman Badillo famously turned to his opponent, Abraham Beame, pointed his finger, and called the diminutive city comptroller “a malicious little man.” Mr. Badillo lost that election, and his subsequent mayoral runs, too.

For the upcoming mayoral debates, several political strategists point to a golden rule: Do not make mistakes.

The veteran NBC reporter Gabe Pressman moderated that debate, and dozens of others over his 51-year career covering city politics. Yesterday he remembered that Mr. Badillo’s outburst represented the triumph of a Beame strategy of baiting his opponent.

“It was not so much that Badillo said he was malicious,” Mr. Pressman said, “but that he insulted all the little men in the city, and there are a lot of them, including myself.”

The four Democratic mayoral candidates this year, Fernando Ferrer, C. Virginia Fields, Gifford Miller, and Anthony Weiner, are set to square off Tuesday night at Jazz at Lincoln Center and to spar at least once more on September 7.

There is also the potential for a runoff debate on September 22.

The debates are arranged by the city’s Campaign Finance Board and required for all participants in the campaign finance program who meet certain qualifications.

The last forum among Democratic rivals, on July 28, was shown on the NY1 cable station and was watched by an estimated 16,100 homes in the first hour, averaging 10,700 homes at a time over the course of the 90-minute program, according to NY1.

“It’s a fair bet that more people will be watching the Yankees or Mets,” the senior adviser to the Bloomberg campaign, William Cunningham, said yesterday.

But Mr. Cunningham noted that not all mayoral debates are ratings flops. Nearly a million viewers tuned into an August 1989 debate among Mayor Koch, David Dinkins, and others in a tight mayoral contest.

Mr. Cunningham said Mayor Bloomberg expects to debate an opponent “at some point.” The adviser said that because Mr. Bloomberg is paying for his own campaign and not participating in the city’s campaign finance program, he is not obligated to join the board-sponsored debates.

In 2001, Mr. Bloomberg engaged the Democratic nominee, Mark Green, in two televised debates. Regardless of how many viewers tune into the upcoming contests, a political consultant, Hank Sheinkopf, who has coached candidates for mayoral debates, said it is not a question of audience size, but of what turns up in the press the next morning.

“The trick is to sound smart, cogent, in control, and be pleasant to the camera,” he said. “Make sure at the end of the debate, you have enough people spinning so you can have the best control of the next day’s news.”

In an attempt to dominate coverage, Mr. Sheinkopf said, candidates will try to break big news around the time of a televised debate, draw reporters to the event, and plant sign-waving supporters in and around the venue.

Mr. Sheinkopf said candidates should find the right balance between “clinical” and “warm.” Candidates should avoid appearing emotional, flustered, or coming across as a “wise guy,” and should concentrate instead on sticking to the rehearsed script and talking points.

Another famous campaign gaffe occurred in a debate for a New York Senate seat in 2000 between a Republican congressman, Rick Lazio, and the first lady, Hillary Clinton. Mr. Lazio walked across the stage to ask Mrs. Clinton to sign a pledge that she would not accept “soft-money” donations, waving a piece a paper in her face.

According to the director of Marist College Polls, Lee Miringoff, Mr. Lazio’s ploy backfired. “It looked like he was bullying her and the net effect – it was a moment he would like to take a redo on,” Mr. Miringoff said.

Mr. Miringoff predicted that this season’s primary debates will have a bigger impact than usual.

For the upcoming primary debates, Mr. Sheinkopf said each candidate should select one significant argument that separates himself from the pack.

He also advised: “Do not be demeaning to any of the candidates, because it might upset some constituency you might need for the general election.”

Another political consultant, George Arzt, said that televised may oral debates are often contests to win newspaper endorsements, and that candidates may follow newspaper editorials to tailor their platform for the papers’ approval.

As for other tailoring matters, Mr. Arzt recommended a light blue shirt and a blue suit for male debaters, and generally muted colors for women. He issued a blanket veto on the color brown, which he said looks bad on television.

Mr. Arzt, who is not representing any mayoral candidates, does not expect any fireworks next week, but he did make strategy predictions.

“Freddy wants to leave the debates unscathed and above the fray, since he has such a large lead,” he said of Mr. Ferrer. “Weiner and Giff keep warring with each other at the debates because they going after the same constituency … basically the white vote. … Virginia is going after her own base.”

If a former leader of the City Council’s Republican minority, Thomas Ognibene, is deemed qualified for the ballot in a GOP primary and reaches certain eligibility requirements set by the Campaign Finance Board and the debate sponsors, then there are two dates for Republican primary debates.

Because Mr. Bloomberg is not participating in public campaign financing, however, he is not required to debate. Mr. Ognibene might then appear alone.