I've got a few works-in-progress that are officially kicking me in bum. For the sake of my sanity, I'm venting here and maybe I can help another author or artist going through the same thing.
When a WIP is driving you crazy, remember:
1) Deadlines are your friend. Nothing gets the creative juices flowing like knowing that something is due...TODAY?!? AHHH!!!!
2) Don't press the delete button. Just don't. As bad as the scene or chapter might seem, a revision later will take care of it. But if the words are gone, they're gone. And the only way to bring them back is to find one of those Harry Potter hourglass-thingies or a nuclear powered Delorean that can take you back in time.
3) Outlines are awesome. Write one. Then, ignore it. Sometimes a fresher, better idea will come time if you're not shackled to the scene-by-scene rundown.
4) This is for artists in particular: Every once in a while, a drawing just wants to come out ugly, period. Don't fight it. In fact, make the drawing as horrible as you can, then rip up the piece of paper into a bunch of tiny pieces and throw it out. Doing that is like sending the creative part of your brain on a trip to the spa. You feel refreshed, rejuvenated even. And when you sit back down at the drawing table, you know you've already gotten that ugly sketch out of your system and now you can draw something attractive.
On that last note, I'm heading back to the drawing board to finish penciling. :)