I've tried a few techniques to deal with writer's block. The first, and most obvious, is to just step away. Go watch a movie, or play with the dog. Clear your mind. Once you're not so stressed, come back and try again. Another way I tried was to jump from that project to a different writing project. By the time you finish, perhaps the original story will be ready to come out. Fantasizing about my characters as I go to sleep is also beneficial when I have written myself into a corner.