Start with some stretching exercises to loosen your muscles.
1.Begin in a position so that your upper body is straight. Don't arch your back or hunch. Tuck in your butt so that it also aligns with your back. Bend your knees slightly and never, ever, lock them.
2.Use your stomach muscles to 'pull' or lead your hip movement; the lower back should not have a large arch. Some schools insist on the stomach pulling from the start, in order to train your stomach. (Hence the name, belly dancing) If your prefer this way, the movements initially show less, but develops stronger movements. The hip movements first, is slightly superficial, and will never fool a pro, until it is perfected with the stomach pulls. Also, improper posture can cause problems in the lower back.
3.'Separate' your upper body from your lower body. The movements are very different: The ribs upward (Especially arms) focuses on 'flowy', languid graceful movements. (Often referred to as goddess or heavenly movements) The stomach downwards, to the feet have more strong, bold, quick and precise movements. (earthy movements).
4.Move side to side (which works well if you're hippy and small chested) and back and forth (which looks great if you're busty with small hips-since the side movements show less movement)
5.Divide your torso (mentally) vertically down the centre. Try to move one side of your hip up and down, back and forth etc. The trick is to keep everything else dead still while one side of your hips work.
6.Try 'drawing' little circles in the air with your one side. As you get the hang of it, try 8's, arcs, swirls etc. Don't forget your other side. One side will always be easier, or stronger, depending on whether you are left or right handed.
7.Alternate by trying different combos, like left hip circle, right hip circle, two rights, two lefts etc, always using your stomach to pull your hips in different directions.
8.First find your diaphram by making the "K", Sound. The diaphram muscle is on the top of the abdomen and just below the rib cage.Practice your stomach ripples (that causes the back/forth movements). There are three main muscles used: (1) a crescent shaped muscle just above the pubic area; (2) The area between the 1st muscle and below the navel; (3) just above the navel to your ribs (the one that hurts when you laugh too hard).
9.Try isolating or clenching each one individually. First 1, then 2, then 3. This, once mastered is the basis for the stomach ripple. Once the individual clench1, clench2, clench3 is mastered, try release1, release2, release3, just after the consecutive clenches.
10.Add some music, (good, strong, repetitive bass) and try matching the type of movements (earthy or heavenly) to the tempo.