There are definitely a few tricks for it. The main being that I (and many other artists) draw at at least twice the size I want the finished image to be. That way, when I resize it, flaws aren't as noticeable. I also, however, draw the line art over top of the original sketch at about 300+ zoom, and go back and erase anything that isn't to my liking (it's a lot of zooming in and out). Also, pressure sensitivity. It is the best.
The main one, though, is a total cliche: practice. I practiced with my tablet a lot in order to be able to draw with a steady hand.
I hope that helps!