Patience, confidence, openmindedness
First of all: to become a skilled artist, you 'must' work. Fortunately, you need neither talent nor imagination; they can be trained. That being said, there are virtues that will help you stay sane.
You'll want to be a master tomorrow. Sadly, that won't happen. You need to be patient with your overall progress, and every piece of work. But look back to what you already achieved; date your drawings to see your progress. Find the incentive that keeps you going on grey days (maybe you want to create, say, a graphic novel. Dangle that wish in front of you like a carrot and chase it).
Don't mistake confidence for cockiness. Some beginners think their work is award-worthy when it isn't. Eventually, you will realize how much you simply don't know; don't worry, all artists learn all their lives. The good news is, that you will also realize what you 'can' do. The thing is that being afraid of the canvas won't bring you forward, and that's what you need confidence for. The very fact that you strive for improvement is reason to be confident. Never be afraid of failure - 'getting out the bad stuff before you can paint the good stuff' is true. So paint a lot, you'll get good.
"Leave your comfort zone": do not stick with one genre or style. Say you like anime; try realism, maybe you'll like it. Being afraid of colour theory or perspective is needless, they're actually nice guys when you spend some time with them. Don't deny reference sources; from particle colliders to fashion shows, anything can inspire. Try different media and artforms, like digital, acrylics, typography, collage, sculpting... Every time you try something new, you will take something back to your regular work and improve.
These are just some thoughts about the general mindset that helps becoming an artist. So much time was lost because I stuck with one art style, because I was scared of the empty canvas, because I just wanted the thing to be finished. Now that I take my time, just start painting, and am ready to change it midway, my artwork is much better.