Watch clips of hip hop dancers in music videos on the Internet or on TV. Study how the dancers move. Notice how many different hip hop dance styles there are.
Practice the hip hop dance moves you see in the videos. Don't worry about how you look at first. Just try to get the basic moves down. Allow yourself plenty of space for moves such as spins, jumps and kicks
Set up a group of dress mirrors in your room or garage, if possible. The mirrors should be 5 to 6 feet tall and placed along one wall, so that you can watch yourself as you practice your dance moves.
Dance against other people at clubs and parties. Hip hop dancing has a strong tradition of competition. Battle dancing is a popular past-time in the hip hop world. You might lose, but you will likely make a few friends that can share dance moves with you, or help you with your own.
Register for a hip hop dance class. This will help you learn the basic movements properly. These should be simpler than the moves you've practiced on your own. Continue taking classes and moving up through the ranks.
Watch dancers from contemporary, salsa, jazz and other backgrounds. Borrow moves from other backgrounds that you like. Combine those moves into your own personal style.
Master one particular hip hop dance move. By having one specialty you are sure to be good at one thing. Even if you are only an okay hip hop dancer, you will still have that one specialty.