One of the most important things a PM does is choose people for senior Cabinet roles. These choices are best based on talent, energy and understanding of the jobs concerned. Whilst of course the overall balance of the Cabinet has to take into account wings of the party, geographical spread and loyalties these should be secondary issues to the more normal matters in selection that are related to being able to doing the job well. Cabinet members do not get a phase in or training period when they first join. They are expected from Day1 to be able to make decisions, defend their department and show knowledge of their topics regardless of their background and experience.
The PM should have regular review meetings with the senior Cabinet members one to one. These meetings should be to give guidance to a Cabinet member over PM preferences and how the departmental policy and priorities can fit into the general strategy. They are also occasions when the Cabinet member can ask for support and assistance, and the PM can show understanding of a colleague’s plight and mentor where necessary. As there are too many Cabinet positions to report one to one to the PM senior Cabinet members should perform the role for more junior Cabinet members. The Chancellor should guide the Chief Secretary, the Foreign Secretary the Overseas Aid and Trade Ministers etc.
Cross departmental strategies like levelling up or greening government should come to Cabinet for determination. Conflicts between departments over issues should come to cabinet or committee for resolution. A Cabinet member should be held responsible for a policy entirely or mainly within their own department. So the Chancellor should be responsible for tax strategy and the Home Secretary responsible for migration policy. Given the importance of these to government as a whole the PM should keep them under review in the one to ones and they should report to Cabinet regularly as well.