The first thing you need to do is find out if you're any good. Writing is not as easily quantifiable as, say, pole-vaulting. A really long ruler will put a number to your abilities in a jiffy. Words on a screen (or on paper, if you've gone old school, or have enough confidence to risk the trees and ink) aren't strictly measurable.
The good news is that literary accomplishment comes in many flavors. The bad news is that literary accomplishment comes in many flavors. The difference between a crème brûlée and a cream-of-something-that-tastes-of-the-plastic-container-in-came-in is subject to opinion, at least to a degree. These opinions, if they were all written out, could fill many dozens of very dull libraries. You could always ask your mother, but in most cases, you'll just come back knowing that your mother loves you. If you're the sort of person who confuses maternal affection for valid currency, it could be a long road.
For me, I found a mentor and writing coach online on a writer's website. The two most important things to consider when trusting your ego and your words to another writer are these: that he (or she) be a better writer than you, and that he understands what you're trying to accomplish. In my case, it wouldn't have done much good to seek advice from a children's fantasty writer. But it's the first point that's crucial, and tricky. If you're lucky enough to find someone truly talented, who is willing and able to guide your writerly evolution, it can change your life.
Here's a quick rundown of the pros of electronic tutelage:
-contact with someone who knows what the hell you're talking about (This may seem terribly basic, but believe me, in a real life full of normal people, someone who understands the demands of constant day-dreaming is gold.)
-negative reinforcement (Go ahead, see how quickly you stop mistyping 'your' for 'you're' after being mocked for it a few hundred times. You'll still do it anyway, but you'll learn to be more careful.)
-a thick skin
-perspective (You always know what you meant. The test is, did it come across in the words you chose and the order you put them in? My mentor and I have a rule - if you have to justify a passage after criticism, it probably just needs to be rewritten.)
-patience (My writing advisor is 4,000 miles away and keeps ridiculous hours. As available as he makes himself and as generous as he's been with his time, I still have learned to better handle the itch of "did you read it yet?! How 'bout now?"
-the thrill of approval when you've gotten it right (There's nothing quite like applause from someone you deeply admire.)
The only downside, as I see it, is in the usual shortcomings of email. Specifically, tone can get lost. Electronic misunderstandings can really screw up a good day. Any frustration or hurt feelings sustained in the critique process would happen anyway, because inevitably, you'll get it wrong. A lot. And someone is going to point it out. Wiping the tears from your eyes while making rude gestures at your computer monitor in the privacy of your own home lets you keep your reputation of civility. So go ahead, get mad. He can't see or hear you.
But if you're becoming a better writer, then make sure you thank him where he can see it.