Also, you might want to check out this newbie thread. We're a bunch of rank amateurs working through tutorials and assignments so we can improve our art. Or "art", as the case may be. I'm one of them. Join us if you like.
I've found that it's encouraging to keep a log of how much I've been drawing. I have a giant spreadsheet with descriptions of all of my drawings (even the rubbish ones) itemized by time taken, date, media and sketchbook. This way I can compare one drawing with another of a similar subject that I've done with n hours more of experience. Looking at drawings from the same month might not be that impressive (unless you're an extremely focused art machine), but after a while, you can see that you really are improving. Also, you can compare how much time you've spent drawing to that magical 10,000 hours after which one is supposedly a master. Although it will really depend on how far you stretch yourself with each piece, until you've started to approach 10,000 hours, you can always tell yourself that as long as you stick to the right path, you'll eventually be able to create art like you want/at the quality of your idols.
Best advice i can give is to just buckle down and start figuring out what kind of stuff really inspires you and draw the shit out of that stuff.
Read books on art, peek around here at what some of the pros are doing in terms of quality, content, etc. But really just find someone or some people who really inspire you and just make that your longterm goal. Longterm goals can take you far, and really if you have a concrete goal in terms of your art, your mind will fill in all the blanks of what you need to get there.
The real key is that there isn't some secret or trick to make a person a better artist. There's a bunch of little tricks but the real key, in my experiences, is inspiration (goals) driving learning, and the filler is just putting in the hours. Stay inspired, let the inspiration drive what you learn, and work hard. It doesn't matter where you are now, do that, and you'll surprise the shit out of yourself.
"I must not fear. Fear is the mind-killer. Fear is the little-death that brings total obliteration. I will face my fear. I will permit it to pass over me and through me. And when it has gone past I will turn the inner eye to see its path. Where the fear has gone there will be nothing. Only I will remain."
--- Frank Herbert, Dune - Bene Gesserit Litany Against Fear
Check out my Sketchbook! Critique and Criticism welcomed.