You will launch many projects, but have time to finish only a few. So think, plan, develop, launch and tap good people to be responsible. Give them authority and hold them accountable. Trying to do too much yourself creates a bottleneck.
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.