I do what I call writing through it, that is basically what everyone else said. I force myself to write-even if I know that I'll probably delete the whole thing eventually. Once I get myself started that usually works. I listen to music and that helps me. For me, being disciplined with it helps, too. I write something on one of my stories, even if it is only a few sentences, every day. I think in the five years I've been writing, there has only been one day that I did not write at least a paragraph. Thinking it out ahead of time and having an outline helps me, too. Sometimes research for the story gives me ideas and helps me to write.

Best wishes!