I've been practicing at photography for a while, and there's a few things I've learned that I think applies to most any thing you want to be good at.
1) Practice before you stick your neck out.
What do I mean? It's nice to show off photos you've taken after the fact, but if someone expects you to take pictures of THEM and get good shots, well you better be ready. Better to take 400 pictures of plants in your backyard every day for weeks so nobody knows you take 399 bad pictures for every one good one. You can always take pictures of friends later after you have improved your ratio to something better, like 200 to one. :-)
2) Every professional works from a bag of tricks that he repeats and builds on, but still has a basis in some trick he knows.
In photography you might have a few basic shots down before you're ready to go out in the real world. The more 'tricks' you can do with your eyes closed, the more professional you'll be over all. A professional doesn't invent new shots every time he lifts a camera. He adds a slight twist to a shot he's done hundreds of times before.
3) Learn a few tricks, but learn them very well.
When first starting out, learn a portrait shot or two and an outdoor shot or two. You learn to do a few shots really good, and then explore a new technique with each shoot. With that plan, you're sure to get a few good shots out of every try, and maybe another unique shot as well. Learned a good lighting technique and pose? Shoot it another 100 times. Make it natural. Be able to do it in your sleep.
4) Constantly be looking for new tricks.
If you only learn 5 or 6 'tricks' and stop, you stagnate.
By trick, I mean things like the perfect headshot, or maybe landscapes with a huge rock in the foreground. Focus on one aspect and improve.
I'm still learning my first trick, but hey, WalMart finally refused to print a photo without a hassle, because it looked 'too professional' so I guess I've hit a milestone. Time for another trick.