I came across a quote that a friend posted on Facebook today and thought it was a really cool analogy for writing.
Writing is a muscle. Smaller than a hamstring and slightly bigger than a bicep, and it needs to be exercised to get stronger. Think of your words as reps, your paragraphs as sets, your pages as daily workouts. Think of your laptop as a machine like the one at the gym where you open and close your inner thighs in front of everyone, exposing both your insecurities and your genitals. Because that is what writing is all about.
To read the entire guide to writing, check out this post: http://www.mcsweeneys.net/articles/the-ultimate-guide-to-writing-better-than-you-normally-do