That's an easy one. I haven't really had to deal with writer's block too often, because I feel that writer's block is more a state of mind. I feel I need to be in certain moods to write certain stories. There are three things I usually do if I get stuck with what I am writing:
1. Lie down and listen to music from a playlist that I set up for the story. Usually that brings about the images/scenes from the story that I'm writing and I can get back to it.
2. Start writing something else that involves a totally different set of characters and different genre. Sometimes that will mean jumping onto one of the Goodreads writing groups and doing some random writing there.
3. I leave it and play with my daughters or do something that has nothing to do with writing or the story - eventually the story returns when the mood hits.