Hi Mr Lee
Have you looked into clicker training at all? The clicker is a great training tool, though it's certainly possible to train without it. Check out clickertraining.com or kikopup (on youtube) for more info.
I know a lot of young Staffies/pitties and there tend to be two training hurdles IMO.
1- These are big, strong dogs whose physical maturity often goes ahead of their ability to control themselves. This isn't a specific pit bull thing, there are a ton of dog breeds with the same trait. Medium-to-large "exuberant" breeds often need to be helped to learn how to restrain themselves. Notice that I say that dogs can learn to restrain themselves! It's not a matter of teaching the dog to wait for your command in every instance -- it is entirely possible to teach a dog self-restraint.
2- Pit bulls/Staffies tend to be very clever dogs. How is this a training hurdle? Because while you're plodding along at a normal human pace, the dog is five steps ahead. It can be hard to capture/reward the behavior you want because the dog has thrown out 3 different behaviors in the blink of an eye. The up side of this, though, is that once you and the dog hit your stride as training partners, the sky's the limit :-)
As far as what your dog knows to do in the house -- does she really know it? Will she "sit" wherever she is when you say it, or will she walk in front of you and then sit? Will she respond to the "sit" cue if you raise both arms above your head? Wave them around? What if you're sitting, or not facing her? If (for now) she's too out of control outdoors, work on your indoor stuff so that you know she really knows it. [Important! A lot of people mistakenly think the dog is being defiant when she doesn't 'sit' on cue -- unless you've taught her to sit while you're waving your arms, she's not being defiant, she just doesn't really understand what 'sit' means!]
"Stay" exercises are a great way to start to teach self control. Teach her to stay put while you prepare her food, while you get her leash, while you put your shoes on to go out, etc. You may need to start with less exciting times, but you'll work your way up to having her stay while you open the door to the outside (while on leash, of course). She'll learn that good things come to dogs to wait :-)
For other resources, see Leslie McDevitt's "Control Unleashed" puppy book; Sue Ailsby's Training Levels (this is VERY detailed, step by step training plan, if you're interested in that), Pat Miller's Power of Positive Dog Training, and kikopup on youtube.
Best of luck and, as others mentioned, if you have specific questions, please feel free to ask.