Watch a Bollywood movie such as 2007's "Jab We Met (When We Met)." Notice the body positions and patterns of the dancers, such as tilts of the torso and head, hip bumps moving up and down, feet moving from side to side and forward and back, arms overhead, on hips and in front of the mid-section, hands movements, gesturing "come here." Listen for rhythmic changes such as 1,2...1,2 to 1,2,3...1,2,3 to 1,2,3,4...1,2,3,4. Since Bollywood performances usually include a romance between man and woman, notice the role of the man as fierce and strong, and the woman as playful and lively. These roles are accentuated by deep knee bends and hopping motions.
Go to a dance studio that offers Bollywood dance classes. Some classes will teach the Dandiya Dance, which is performed during an occasion called Navratra, or Bhangra Dance, which is performed during a holiday known as Lohri & Esakhi.
Practice Bollywood movements of the hip by placing your weight on one side while moving your hips up and down. For the feet, practice doing a side step by moving the right foot to the side and allowing your left to come together, then reverse it. An additional foot movement would be to move onto the ball of the foot and back down in the 1,2,3 rhythmic pattern. For the arms, practice reaching upward (as if you're stretching) while turning the elbows in and out. Slowly learn these moves until you're able to speed them up to the lively Bollywood sounds.
Check out Bollywood dance lessons available online; some of which are free through youtube.com and some charge a fee, such as bollywoodfitness.com (see "Resources").