Sometimes when I work too long on a project, or I'm just gearing up on a new piece of work, I get stuck. Can't make anything happen. Nothing looks right or everything looks forced. It can be very frustrating. I'm finally learning that walking away is a good thing. Even if it's just for an hour. That can be very hard to do if you're on a tight deadline. But looking at something with fresh eyes (or rested eyes...and I'm talking naps here) really helps.
The other thing I've found that I love, is to work on my ipad (thank you Steve Jobs). I love the ArtRage app and it gives me a lot of freedom to just play around that Photoshop doesn't seem to do. Maybe it's because I can just plop myself in front of the tv and just play and let my unconscious do the work. And maybe it's because the stylus is a little thick and reminds me more of a crayon than a pencil. Makes everything look a little more childlike which is a good thing when you're a picture book illustrator. And maybe it's because the stylus actually touches the screen, like a Cintique. (I use a Wacom tablet with my iMac and Photoshop.) Whatever it is, it seems to be a good problem solving tool for me.
And, of course, if all that fails, there is always chocolate.