If I get stuck with a piece of writing, I usually walk away and do something else. I might go for a walk, tidy up, do the dishes, have a shower. What I don't do is keep sitting in front of the computer surfing the interweb or going on Facebook. I think getting up, moving around and doing something physical clears my mind, then my subconscious can start trying to find a solution. Before I sit down at the computer again, I might scribble a few notes in my journal, tossing around a few ideas until something clicks. I might also ask myself what's gone wrong with the story before that point. Perhaps I've made a wrong turn ten pages ago, maybe I don't know my main character well enough and that's what's tripping me up. I don't panic, I don't rush, I don't stress; those things will kill your creativity and you'll be stuck forever. Sometimes it's an easy fix, sometimes it means you're going to have to go back and make some serious changes, but it's important to remember it happens to everyone and there's no need to beat yourself up about a speed bump in your writing. And that's the way I like to think of it, not as a block, but just as a bump.