Humor is very very risky, particularly for a candidate, unless he's been in so long that it just doesn't matter, and he's not running for president. But it's just that people are so sensitive and so touchy, and you're just going to upset somebody without ever realizing it.
If in doubt, move decisions up to the President.
If you foul up, tell the President and correct it fast. Delay only compounds mistakes.
In our system leadership is by consent, not command. To lead a President must persuade. Personal contacts and experiences help shape his thinking. They can be critical to his persuasiveness and thus to his leadership.
Leave the President's family business to him. You will have plenty to do without trying to manage the First Family. They are likely to do fine without your help.
Be able to resign. It will improve your value to the President and do wonders for your performance.
Don't be a bottleneck. If a matter is not a decision for the President or you, delegate it. Force responsibility down and out. Find problem areas, add structure and delegate. The pressure is to do the reverse. Resist it.
When asked for your views, by the press or others, remember that what they really want to know is the President's views.
The price of being close to the President is delivering bad news. You fail him if you don't tell him the truth. Others won't do it.
Look for what's missing. Many advisors can tell a President how to improve what's proposed or what's gone amiss. Few are able to see what isn't there.
When you raise issues with the President, try to come away with both that decision and also a precedent. Pose issues so as to evoke broader policy guidance. This can help to answer a range of similar issues likely to arise later.
Make decisions about the President's personal security. He can overrule you, but don't ask him to be the one to counsel caution.
See that the President, the Cabinet and staff are informed. If cut out of the information flow, their decisions may be poor, not made, or not confidently or persuasively implemented.
One of your tasks is to separate the "personal" from the "substantive." The two can become confused, especially if someone rubs the President wrong.
Preserve the President's options. He may need them.