When I'm asked what it takes to become an artist, my first response is tenacity.  The ability to continue making art no matter the rejection, of which there is plenty.  Just keep working and working a lot.  To paraphrase Vonnegut, if you do anything long enough, you get better at it.

Do your homework, woodshed, and get it out there.  I paint 6 to twelve hours everyday, even though I have a full-time day job. Work work and work!