I zoom in and work on my linework pretty diligently. Lots of small strokes. The tablet is going to pick up all your hand jitters, and I have shakiness, so I have to compensate. You're not going to be able to draw a single continuous line without it being shaky. So, it's best to draw lines in short strokes, as you have better control. If I want to draw a nice curve, I use the Pen Tool.