I don't generally get writer's block, but when I do feel stuck midway through a story, I try to suss out the heart of the problem. Sometimes it's that the story took a wrong turn or a character does something inconsistent with their personality. A day away from my writing usually allows my subconscious to work out what's wrong. Once I figure it out, the words come more freely. At that point, I'll make the appropriate changes and move forward in the novel.