Can you be more specific about what you want to draw and what you're having trouble with? Maybe some samples of your work as well.
It doesn't matter if you're drawing on a tablet or on paper, understanding the fundamentals of form, perspective, color theory and preferably some art history are what will help you become versatile with any medium. Practice, self-critique and exploration of different styles and techniques is what will eventually help you develop your own style. Unfortunately, there is no program or tool that will make your work look instantly good.
As far as tablets go, I used a small Graphire when I first started with digital art and eventually moved to slightly less crappy Intuos 2, which I used for about 6 years. Drawing with a tablet is strange at first and has a bit more of a learning curve than drawing on paper because it's not quite as natural, so it takes a bit more practice. It took me a few years before I was comfortable with drawing freehand with a tablet.