When you're skiing, if you're not falling you're not trying.
"Do you have any regrets?" Of course I do.
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.
The worst thing you can do is allow a coalition to determine what your mission is.
Politics is human beings; it's addition rather than subtraction.
Watch the growth of middle level management. Don't automatically fill vacant jobs. Leave some positions unfilled for 6-8 months to see what happens. You will find you won't need to fill some of them.