What do you actually do to replenish your willpower?

After a bit of brief research, I still have no idea how willpower depletion actually works, or if I’m mistaking depletion for distraction, etc., etc. I get the impression that there isn’t much a consensus in the field on this subject.

What I’d like to know is this: what do you actually do to replenish willpower?

In other words, after working for several days in a row and being tired and not wanting to work on project x that has a large delay and little expectation (from the Procrastination Equation), how do you then work on project x? Do you eat something sugary, recite a mantra, meditate, sleep?

I’ve read (I can’t remember where) that completing difficult tasks gives a boost to willpower, but then how do you convince yourself to start that difficult task? And what difficult task do you use?