Write.
Even if you have other things to do.
Even if it sucks.
Even though it's hard.
Even though there are no guarantees.
Even if no one else cares.
Revise.
Even though it's difficult to be objective.
Even if you think you got it right the first time.
Even though you hate it.
Even if you're sure it's a waste of time.
Submit.
Even if it's to a small, non-paying publication.
Even if you feel you're not ready.
Even if you hate rejection.
Even if you know you'll never be accepted.
Repeat.
You're a writer. Act like one.