It is quite hard to break habits, but not impossible. It will not happen over night. I try to draw long gestural lines from my shoulder. You get a wider arc and although it seems a bit weird at first, once you get used to moving your muscles in this way, it will seem like second nature. I use my shoulder for the basic structure of the form I am drawing and the all important gesture. For closer, detail work I move down to my wrist and fingers. The only way to practice is to practice.
I would also say that you should think about the form you are drawing rather that the contours. Everything you draw can be made up from cube, spheres and cylinders (I am misquoting someone here, although not sure who). I am havng to retrain my brain to think in these ways because I really want to learn how to draw "properly".
I'm not sure how to tell you how to colour. There are many things to think about, such as the way light hits the subject, the translucency of the subject, direction etc. Colour - saturation, hue & value are all relative to each other (and themselves). It's all complex stuff. Don't try to learn too much at once, try to keep it fun.
I've tried Photoshop and painter. They both have pro's and con's, but are quite similar in many respects. I would focus on just one at the moment. The important thing is the drawing and painting not the program you are using.
1-2 hours a day is plenty time. As long as you do it every day. Your brain can only absorb so much per day. As you develop you can increase the time you paint each day if you wish to become professional.
Keep it up. You are doing great!
My other tablet is a Cintiq
