- Draw for yourself, not an audience!
The first and probably most important point, especially for any artist on here who in one way or the other seeks feedback and recognition from their fellow deviants. You should never forget that your art is after all YOUR art, so it should be a means to express yourself, relax yourself, be proud of yourself etc and not anyone else. Never let yourself be pressured to do anything you don't want simply because your watchers might demand it or do anything for the sole purpose of getting more attention. It might make you happy in the beginning but loosing track of what art actually means to you and the things you really like to express with it will come back to you in the end.
(The only exception to this might be people who do art for a living. ;) )
- Find your own pace
It can be easy to rush yourself, to feel like you should be 100 times better with every drawing you do but that is simply not possible. Take it slow, especially if you're still young. You got your whole life ahead of you to improve. Do things step by step, not everything at once. Pick out those areas you know you want to improve at and concentrate on them instead of the whole thing or you'll feel overwhelmed and discouraged easily. No one can be a pro from one day to the next. Everybody advances with a different pace, you can't expect to get exactly the same results as someone else in the same time span. Which brings us to the next point.
- Don't compare! Analyze!
This is probably one of the main things that makes a lot of artists feel bad about what they do. They constantly compare themselves and their art to others. Funnily enough we always compare ourselves to those who are better, often way better than ourselves, never to those who are behind us in skill and experience. And it can get more than frustrating to see how good others are while you feel that you are still miles from that stage.
Yet there will always, and I repeat ALWAYS be someone better, more skilled, more experienced, more famous etc than you. Not even necessarily because they really excel you but simply because you perceive it like that. Why is that? Because an artist is their own worst critic. That's right, you yourself will always be the one seeing the most mistakes and errors in your art, things that an outsider might never notice unless you point it out to them.
That in itself is a good thing because it keeps the will to improve alive but the thing you need to avoid is to keep comparing your works to those of higher skill and seeing it as blows to your own art. See it as a chance to improve! Look at works of artists you admire and analyze them! Dissect them bit by bit and see what they do different to yourself, how you can apply what you see to your own techniques.
- Learn how to deal with critique
It sounds so obvious but it can be harder than you think. In particular here on dA where you will sometimes be confronted with feedback you didn't actually ask for. And even more so some of the critiques you will get might not be as friendly as you'd like them to be. They might point out faults that you can't quite comprehend or mark things as flawed that you were actually really proud of.
Don't let those things get to you, don't let them discourage you! Once again you should see it as an opportunity to improve. I won't say that you can't become a pro all by yourself but you have a much better chance if you take advice and tips from others. Don't be too proud to accept their help. And should you ever feel that any feedback is highly unfair, then simply dismiss it instead of obsessing about it. It takes some strength of will to do so but if you let all those negative comments gnaw on yourself it will slowly eat up your drive to continue at all.
And last but not least:
HAVE FUN WITH WHAT YOU'RE DOING! :)