Always remember that when you teach new tricks it is important to continue to review old tricks as well. Dogs are like people in the sense that they sometimes forget what they did yesterday.
Once your dog has learned the basic commands of Sit, Lay Down, Roll Over, and stay you can move on to something more difficult. With my young dogs I play a game of "Name that Toy", where I say a toy name and the dog goes and picks it out. Training for this game takes some time and patience but it teaches a lot the skills that the dog will use later, including releasing the toy after he has brought it back too me.
Always remember to keep training sessions fun, this is good for both you the owner and the dog. By keeping it fun the dog will look forward to learning new things, and you the owner will be amazed at how capable the pit bull is at learning.