No matter what type of art you're into, the main thing you need to do is to be consistent in working at it.
For instance, if you're drawing something, work on it a little bit each day, even if it's just for 5 minutes. There were many days when I just didn't feel like working on this portrait of John Lennon, but I did it anyway. By being consistent in making progress on the drawing, I was able to finish it in a month -- I know that's still a long time, but it took a lot less time than any of my previous drawings.
Thanks! I haven't uploaded any more drawings because I don't really have very many. I plan to be doing a lot of drawing next year though; I have something specifically planned to do then, so there will be plenty more.