Writing is rewriting, and whether it's good or bad stuff it takes about the same amount of time to rewrite a first draft.
Speaking as someone who has spent years competing as a writer for jobs and recognition, I will tell you that this is among the most important things to keep in mind. In the long run, persistence is more important than talent. You can develop the latter over time, but you can have the former just by making the decision.
(Image via Scriptapalooza)