Why do you want to write?
This is a major question, because it helps you to set goals. If you have a story you want to tell, then your main goal will be to tell the story as accurately and as entertainingly as possible. If you want to teach a lesson, then you want that lesson to be clear and understandable, and, possibly, as artistically conveyed as you can. Are you writing for yourself, or someone else (audience)? Understanding these things will help you set guidelines for your first (or second, or third, or infinite) writing project.
I suggest putting a brief answer to the question "Why do I want to write?" on the wall above your desk, at the top of your computer screen-- somewhere nice and visible. When you get frustrated, look back to the answer; why do you write?