I've spoken before about the importance of sitting down and writing, even when you don't feel like it. It's important, and it leads to progress, even if it's progress that will be undone during edits and revisions.
This will be a short post because everybody with advice on how to write has discussed this topic ad nauseam. So have you written today? If the answer's yes, then good. Go write some more. If not, sit down until you've put AT LEAST 200 words on the page.