You do not need a beautiful belly-dancing costume to get started. Wear anything comfortable that you can move in, including either a flowing skirt to help you see how your hips are moving or a pair of comfortable, stretchy pants with a scarf tied around your hips. Some people recommend the coin belly-dancing skirts, which jingle when you move. This accessory helps you keep your upper and lower bodies isolated, as you will be able to hear whether your hips move when they are not supposed to. You can also hear the rhythm of your movements, which will help you keep time and keep your movements steady.
Once your attire is prepared, find a comfortable, clear spot of floor, preferably in front of a mirror. Music is optional, but many people find that it helps them maintain their rhythm and mind-set. You may also wish to practice in front of a television if you have an instructional video to follow.
Especially if you are belly dancing for fitness, perform repetitions of each type of movement to help tone your muscles. Start with a quick warm up, which can involve anything that gets your body moving and your heart pumping, from a quick goofy dance to jumping jacks to jogging. Once you are warmed up, start with a stretching routine that loosens your arms, legs, neck and sides.
When you have warmed up and stretched, start with the most basic moves. For the hip sway, stand with your feet positioned hips' width apart. Without locking your knees, move your weight onto your left leg, bending your right knee to raise the hip. Switch sides smoothly, and continue to shift your weight from side to side to cause your hips to rise and fall. This should be done in a smooth, undulating rhythm. Once you have this, increase the force with which you raise your hips, causing your hips to pop up on each side. When you speed up the hip pops, you should get a shimmy! Continue to work on reps of each of these most basic movements. You should be able to do these while isolating your upper body and keeping it still.