In this post on goal setting, I suggested:
“The more drafts you create of anything, the better. You can do something once you’ve started. If your computer screen is blank, it will stay blank.”
Read that post for more on drafting.
By the way, I’m using “drafting” in the sense of planning, rather than writing the first version of something or other. Please don’t plan in your head. Get words onto the screen. (Or paper, if you wish.)