This point of the checklist is actually painfully obvious.
It's also the most crucial part of all.
And sometimes, the hardest.
But the thing is, there's a pretty fine line separating writers and wannabes. Both of them write, sometimes -- but only writers do it consistently, and keep up with a project, and don't give up.
I know, I know, it sounds a lot easier than it actually is. Sometimes it's hard, and sometimes it's not so fun. But those aren't the times you write for. You write because you want to, because you have to -- because the people in your brain don't like being ignored, because writing is the only thing keeping you from going crazy.
You write because you're a writer. Laurie Halse Anderson does a great way of explaining this over at http://ywp.nanowrimo.org/node/656611. It's from a NaNoWriMo Pep Talk, but it still applies here.
On that note, why are you still reading this? You're supposed to be writing.