Putting on a bangin’ soundtrack helps sometimes, and regular coffee refills to keep me awake through the first half of the day, but really it comes down to:
Got something you need to do? Start doing it rather than trying to get yourself pumped up to do it. Other than that I find, especially as I’m getting older, that the best way to prepare for getting shit done is to eat and sleep properly. It’s near impossible to focus and do a good job at anything if I’m feeling awful for some other reason.