There are two forms of writer's block. In one, you can't write anything at all. In the other, you are stuck at a particular point in a story and can't figure out what could come next.
This post has a tip for the second situation: interview your characters. Imagine the characters are real people who are experiencing whatever is going on at the point of the story where you are stuck. Imagine that you're a reporter asking them some questions, such as:
* What happened that brought you to this point?
* How do you feel about the current state of affairs
* What would you like to have happen next?
* What do you fear might happen next?
Jot down the answers that come to mind for all your main characters. There's a good chance that these will how you the way forward.