Don't begin to think you're the President. You're not. The Constitution provides for only one.
In politics, every day is filled with numerous opportunities for serious error. Enjoy it.
Control your time. If you're working off your in-box, you're working off the priorities of others. Be sure the staff is working on what you move to them from the President, or the President will be reacting, not leading.
First rule of politics: you can't win unless you're on the ballot. Second rule: If you run, you may lose. And, if you tie, you do not win.
Politics is human beings; it's addition rather than subtraction.
Those who made the decisions with imperfect knowledge will be judged in hindsight by those with considerably more information at their disposal and time for reflection.