Attorney Sheldon Otis is sitting in the wrong seat. He is in the witness chair while his young assistant, Neil Morse, is badgering him with the kind of questions normally heard at any criminal trial.

Suddenly, Otis says "stop!" Morse halts. Otis gets up, and both walk to a TV-like screen at the other side of the room. They begin to watch a videotape of the mock trial.

Otis and Morse are not in a traditional courtroom. They are in their own courtroom, in the basement of the Pacific Heights neighborhood victorian building that houses their offices.

There Otis, one of the most respected trial attorneys on the West Coast, plays with his investment - one that helped him successfully defend Hearst trial figure Steven Soliah on bank robbery charges. And one that he hopes will help him successfully defent Huey Newton in a pending case.

It is an investment that has allowed Otis to market his most saleable commodity: His considerable talents in courtroom presentation. A master of the nuances of the courtroom - the art of questioning, "Coming across to a jury," the psychological and sociological aspects of any trial - Otis uses his custom classroom to train lawyers in his art.

The room is wood-paneled, complete with witness chair, jury box, raised judge's chair, gavel, American flag, and that little something extra - a videotape system.

Actually, the court serves a dual purpose. Otis and Morse uses it to grill potential witnesses on tape, and play back the performance to the witness. Then, they go over the problems - no eye contract with the jury, looking up too much, looking down too much, using "uh" too much, and on and on.

The second purpose is the business of teaching lawyers, many of whom have been practicing for years, something they couldn't learn in law school: how to act in court.

"I teach lawyers trial practices," says Otis. "It's one thing to sit around a conference table and talk about it, and it's another thing to do it in a regular courtroom. Some people who graduate from law school have almost no experience trying cases. Many times they don't even know the basics - like where the plaintiff's lawyer sits and where the defendant's lawyer sits, and where the lawyer should stand when addressing a jury or examining a witness."

"Everybody is always surprised when they see themselves on tape," Otis says. "Lawyers are usually more astonished than anyone else about how they look or come across."

Most of Otis' former students agree. Take Tom Turcotte, who had Otis as a professor in 1976 at the New College of Law in San Francisco.

"I loved it," Turcotte said of Otis' courtroom class. "I learned that my demeanor was all wrong. I would ask the right questions of the witness, but I would ask them in the wrong way. When he (Otis went over the tapes with me, I could see I was more surely than I should have been, and I found that the answers I would get from a Friendly witness would be a lot better if I would just be more pleasant."

Another former student, Lim Bainchi, said of Otis: "He taught me body language . . . like where to stand, where to look, how forcefully to speak, how chummy to be with a defendant - that's important. If the lawyer and his client appear to have a close relationship, then a jury that respects the lawyer will be more likely to respect the client because of his relationship with that lawyer. And the videotaping is also an effective tool . . . it slaps you in the face with your faults."

"Lawyers spend thousands of dollars on Xeroxing, libraries, a lot of things lawyer spend money on - other than trying to help their clients feel comfortable and be realistic about what goes on in a courtroom," Otis says.

"There is no reason that any firm can't have the same setup," Otis says. "You won't believe it, but the whole thing, including the videotape operation, cost me under $6,000, I just can't conceive of a firm that doesn't have one."

"I don't believe a lawyer wins a case," Otis says, "although a lawyer can blow a case. Facts, plus the jurors' attitudes toward the facts will ultimately decide a case. All I can do is a better job than the government."