I just want to say that everything Enoki has said above is 100% true! Like they said, Wattpad is absolutely great! If you do get it, you could follow me at @juniperxcrimson if you like!
Anyways, so what do I have to say...I had a lot of trouble (and still do) with sticking to a story. I'd write a chapter or two and then ditch the entire thing. I've done this for years and it's truly a bad habit, especially considering the fact that some of the ideas are actually good.
Writing FanFiction helps a lot. I'm currently writing a piece of FanFiction at the moment. I'm actually at chapter ten right now and it feels amazing.
Don't pressure yourself into writing. If you don't feel like doing it, then you can't. However, if you do feel like it, and are at a point where you can, do it. You don't want your ideas getting away from you.
Be sure to be descriptive, but not overly so. Make sure that your sentences aren't too long or two short, and that they flow nicely.
Always always always edit your writings. Even if it seems right now, it might not be when you look back at it later.
These are just a few things I've learned over the years...I hope you find something that's useful! Best of luck in your writings!