(1) One of the keys is keeping yourself in the dream. What I mean by that is: Even if you aren't writing, you should consider your project throughout the day. What is your character's favorite color? How would they react if their bus was late? What might surprise them if it happened on the next page of your project? (2) Refill the well. Do/watch/experience things that make you feel creative, make you want to go write. Maybe it's an inspiring class, or a novel, or going to a movie theater. For me, I use the following: Buffy, Graceling, the Harry Potter soundtracks. and now I'd probably add Witches of Echo Park to the list.