To exert dominance you have to force her to do things she doesnít want to do. Such as asking permission: to use the car, for all her outfits, drinking, going out with friends, for any money, etc. You can set her bedtime, limit how much tv she watches, places she can go, curfews, etc.
Or force her to do something beneficial that she has wanted to do, such as exercise, loss weight, cleanout the back room, take up a hobby, go to college, etc.
You could also make her do things that you want, like: buy sex toys for both of you, down load sexual fantasy stories or pics (that should give you an idea of her preferences), wear garter, stockings or other sexy outfits, clean/cook in the nude, etc.
Good punishments are grounding, spankings, light bondage (overnight), and corner time. http://www.takeninhand.com/
is a good resource. Suggestions: Make a written list of rules (you can find pre-made list on the net), Always keep you promises, donít stop just because she cries, show her a lot of attention, and divide the work equally between you.