Shultz acts to position career policymakers. It is seen as quiet process of professionalization

As the second Reagan term gets under way, Secretary of State George P. Shultz appears to be working quietly to professionalize the making of foreign policy and lay the groundwork for pragmatic policies and solid achievements.

Diplomatic observers see recent and prospective personnel changes as a sign that Mr. Shultz is moving assertively to dominate the foreign policy scene despite continuing differences of view and bureaucratic squabbling within the administration. He is managing to put knowledgeable people in important posts and, according to State Department sources, is planning further changes of lower-level positions.

Foreign policy experts laud the fact that professionals are carrying the diplomatic ball in some key areas:

* Paul H. Nitze has been appointed special assistant to the secretary on arms control. Mr. Nitze, the widely respected negotiator in the deadlocked talks on medium-range missiles, will head up the US delegation to the arms control discussions in Geneva next month. The delegation will include the conservative Pentagon and Arms Control and Disarmament Agency ''hawks,'' but they will be subordinate to Nitze.

* Richard W. Murphy, assistant secretary for Near Eastern and South Asian affairs, is now in the Middle East trying to facilitate an agreement for the withdrawal of Israeli troops from Lebanon. Previous sensitive negotiations of thistype were often led by specially appointed negotiators, sometimes without Middle East experience.

* Another State Department officer, Thomas R. Pickering, has reportedly been chosen to succeed Samuel Lewis as ambasssador to Israel. Mr. Pickering, now ambassador in El Salvador, was formerly the US envoy to Jordan.

* Harry Shlaudeman, also a career Foreign Service officer, is now the principal negotiator in Central America, conducting talks with Nicaragua.

Pending questions are who will replace the US ambassador to the United Nations, Jeane Kirkpatrick, and what post Mrs. Kirkpatrick might fill within the administration after she leaves the UN early next year.

President Reagan is eager to keep the conservative Democrat in his fold, but no high-level posts are open at the moment. There is concern among some at State that Mrs. Kirkpatrick would be a contentious figure if ensconced at the White House.

Other, more minor posts may be slated for changes, according to State Department sources. These include the assistant secretaries for economic policy and for international organization affairs. Both are political appointees.

Shultz will also have a new State Department spokesman, Bernard Kalb, following the resignation of John Hughes. Diplomatic experts suggest that Mr. Kalb, a veteran television correspondent, may have been chosen with a view to projecting a more forceful US image.

According to administration officials, Shultz has also established a close and effective working relationship with Robert C. McFarlane, the President's national-security adviser. While both must still take account of Defense Secretary Caspar W. Weinberger and CIA Director William J. Casey views, they now have more weight in the decisionmaking process.

How the new arms control delegation will work out in Geneva, where the President will be facing his first and most important foreign policy issue, remains to be seen. Some analysts say it will be impossible to make progress on a nuclear arms agreement as long as such figures as Richard N. Perle, the hard-line expert at the Pentagon, and Edward L. Rowny, negotiator in the aborted START talks, are a part of the negotiating process.

But others see merit in the President's move to avoid policy and political clashes. ''The only way to hold the talks together and avoid blood in the newspapers is to have all elements involved,'' says Henry Nau, a former staff member of the National Security Council.

''Rowny and Perle will fight for their positions. But they are good soldiers, and once a decision is made by the President they will not undercut him. You have to make them feel a part of the process.''

Stephen Wayne, a presidential scholar at George Washington University, sees the matter differently. ''If you put hard-liners on a delegation that are suspicious of the Soviet Union, all the goodwill in the world will not produce an agreement. That's the problem.''

Playing a leading role in the pursuit of an arms agreement, Secretary Shultz is also trying to involve the President more closely in the process.

Mr. Reagan has not been familiar with the details or sometimes even the broad facts about nuclear weapons and strategies and is reported to be more involved in the issue. ''Shultz is getting directly involved in arms control and wants to keep the President up to speed so he can keep up,'' a State Department official says.

While diplomats at State speculate on further changes, especially at the ambassadorial level, some voice frustration that President Reagan has weakened the State Department with too many political appointees and that the US does not have enough qualified people for key jobs.

''We're not out of the woods on personnel,'' says one officer. ''We keep expanding our objectives around the world and diminishing our resources. It's like 'voodoo economics.' ''