Bit by bit, a sketchy outline of President-elect Ronald Reagan's White House is emerging. It will be, according to chief of staff James A. Baker III, leaner than the Carter White House, congressional relations will get a higher priority and the national security affairs adviser will have a much lower profile than in recent years.

In shaping the new White House, Reagan advisers are relying heavily on the experiences of the Richard M. Nixon and Gerald R. Ford White Houses. And the Reagan White House transition team is made up largely of men who served under the two Republican presidents.

Fred F. Fielding, for example, a deputy to John Dean during the Nixon years, head the counsel to the president transition team. Steve Bull, who delivered to President Nixon the Watergate tapes that later developed a mysterious 18-minute gap, is on the appointments secretary team.

Reagan advisers have rejected the "spokes-of-a-wheel approach" used by Presidents Ford and Carter in organizing their White Houses. Instead, they have adopted a tighter, more direct chain-of-command approach under two main power centers.

Edwin Meese III, Reagan's campaign chief of staff who has been named White House counsel, is at the apex of one power center. He will be the chief White House figure on both domestic and foreign policy. Under him, following a tentative organization chart, are the Domestic Policy Council, the National Security Council and a secretary to the Cabinet.

The leading candidates to head these posts are longtime Reagan advisers Richard Allen, Martin Anderson and retired admiral Robert Garrick, who, if he doesn't become secretary to the Cabinet, is said to be in line for another position close to Meese.

The second power center will be under chief of staff Baker, a recent entrant to the Reagan inner circle, who was manager of George Bush's presidential campaign. "My job is to make the train run, and to cover the political side," he said yesterday.

Michael Deaver, a longtime Reagan aide, will become deputy chief of staff with the rank of assistant to the president, it was announced yesterday. His role will be largely one of logistics and arrangements. A favorite of Nancy Reagan, he will oversee the Office of the First Lady, the appointments secretary, the advance office and the military support office in the White House.

Working more closely with Baker will be the yet-unselected staff director, envisioned as an "alter-ego figure" with assistant-to-the-president rank. There will also be a staff secretary, whose job, Baker told a breakfast meeting of reporters, "is to make sure the paper flow is complete" between Meese's policymakers and Baker's policy implementers.

Baker said he envisions his own job as that of "an honest power broker" between competing interests. Under him, with the same rank as Deaver and the staff director, will be White House press secretary, counsel, director of legislative affairs and political director.

Max L. Friedersdorf, chairman of the Federal Election Commission, yesterday was officially named White House chief for legislative affairs. A former newspaperman and congressional aide, he worked in the Nixon and Ford congressional liaison offices.

In a symbolic effort to upgrade the status of Friedersdorf's staff, it will be housed in the East Wing of the White House instead of in the Old Executive Office Building, where the legislative affairs office is located. Friedersdorf will work out of the West Wing, as does Frank Moore, Carter's congressional liaison chief.

Lyn Nofziger, Reagan's campaign press secretary, will serve as White House political director. Under him, Baker said, will be a series of liaison officers to special interest groups, including women, blacks, Jews and Hispanics.

No one has been picked for press secretary, but the post is to be filled by Jan. 10, Baker said.

Carter aides have advised the Reagan transition team not to cut back the size of the White House staff because "it's the only rudder" the president has to run the government. Baker said he hopes to reject the advice. "We think the leaner the staff is the more effective it becomes, and when you have too many people you have turf battles," he added.

Another major change Reagan hopes to make is to give the president's national security affairs adviser, a post held by Zbigniew Brzezinski under Carter and Henry A. Kissinger under Nixon, "a much lower profile." He said the size of the National Security Council staff will be reduced and that the adviser will have no press secretary. The national security affairs adviser also will not meet alone with the new president, as Brzezinski does with Carter, to give him a daily intelligence briefing.

The briefings will still take place, Baker said, "but with others in the room." This may come as a surprise to Allen, who is generally expected to be national security affairs adviser. Allen has been briefing Reagan daily by telephone without others listening in. As of last night he had not heard of the new procedure.