I went to the learning access center at my college the other day and the person helping me said something interesting: do 5 minutes of something. Even if you don't feel like it is enough, the act of doing it for 5 minutes eases the pressure off of having to do the whole thing, since you already started (for example, homework). I'm still really struggling with this myself, to be honest, but hopefully this advice could be of use to you as well.