In the world of politics, where the aura of leadership is central to winning favor and office, sighting the real thing is an inexact, frustrating science.

The job is even more daunting in other arenas, where the biggest players are not elected and value their privacy and low profiles as much as favorable quarterly returns.

"In the business world, it's harder," observed Frank Mankiewicz, vice chairman of Hill and Knowlton, who managed Sen. George McGovern's 1972 presidential campaign. "You can't just decide 'I'm going to run for leadership' or throw your hat in the ring and force people to notice you."

Nevertheless, in the business and financial community and at the points where it intersects with public policy makers and regulators, some of the following may turn out to be not only people to watch, but also people to follow:

The direction of monetary policy will be decided at the hands of new Federal Reserve Board Chairman Alan Greenspan and Treasury chief James A. Baker III, as might the election if interest rates head higher or inflation heats up.

"The Republicans want to have an election over the economic present -- are you better off than under Jimmy Carter?" said Alvin From, executive director of the Democratic Leadership Council, explaining why the direction of monetary policy and the markets is a key political issue. "The Democrats have to touch peoples' apprehension about the future."

For corporate chieftains with unusually tough challenges this year, interest rates, America's trade performance and consumer confidence are equally important in determining who will be market leaders.

Robert C. Stempel, the new president of General Motors Corp., who is regarded as accessible, articulate and visionary, must sell cars by out-Fording Ford Motor Co. and foreign auto makers on fronts such as design and quality. If he succeeds, it could mean an end to GM-bashing and a renewal of GM market share, which fell to 36.6 percent last year from 41.1 percent in 1986.

Similarly, Stephen M. Wolf, the new president and chief executive officer of United Airlines, must make all the right moves to keep the nation's largest carrier on top in an industry that battles over mere slivers of market share. Wolf faces the tough job of boosting morale among United employees while trying to keep costs under control.

When shock waves hit Wall Street last fall, the door opened for new leaders to emerge to calm the country and to think of ways to avoid a replay of the 508-point drop in the market on Oct. 19.

John J. Phelan Jr., chairman of the New York Stock Exchange, was at the vortex of the storm and is widely credited with helping quell it. Now he finds himself in the middle of the debate over the causes of market volatility and over reforms that might reduce wide swings and uncertainty in the markets.

Intersecting with him will be Wendy Lee Gramm, deputy director of the Office of Management and Budget and the Reagan administration's candidate for chairman of the Commodity Futures Trading Commission. A supporter of the president's brand of less-is-best regulation, Gramm will be tested on how to regulate the fragile relationship between the stock and futures markets and how to determine what agencies should take lead roles in that effort.

Another figure at the center of the post-Black Monday swirl is Peter A. Cohen, chairman of Shearson Lehman Bros., who spearheaded Shearson's acquisition of E.F. Hutton. While others were dumping stocks and retrenching investments, Cohen pushed ahead on the Hutton acquisition, testing whether Shearson can profit from the purchase in an unstable market environment.

The challenge for Gary Lynch, SEC chief of enforcement, will be to push ahead in Wall Street's biggest corruption probe in 50 years. Lynch, who has already snagged headlines this year with charges against a young New Yorker who used millions of investor dollars to purchase luxury items for himself, faces bringing the continuing investigation of investment firm Drexel Burnham Lambert into sharper focus this year.

The career path that Manhattan U.S. Attorney Rudolph W. Giuliani may take is being watched closely for its effect on the outcome of several pending Wall Street cases, including the possible reindictment of Kidder, Peabody & Co. and Goldman, Sachs & Co. executives. It is rumored he may leave law enforcement for political office, possibly after joining a private law firm.

Christopher Edley Jr., issues director for the Michael Dukakis campaign, observed that the lawyers and economists who have gravitated to Wall Street in recent years from top jobs in Washington are well equipped to take leadership roles in shaping and analyzing the relationship between business and government.

The roster of Wall Street brain power includes Robert Rubin, partner and co-vice chairman of Goldman, Sachs & Co.; Roger C. Altman, vice chairman of the Blackstone Group; Jeffrey E. Garten, an investment adviser who left Shearson last fall, and Robert D. Hormats, vice chairman of Goldman Sacs International Corp.

"The most successful people have an intellectual quality to them that gives them something to contribute to public policy debates," Edley said.