The side kick is often described as one of the hardest kicks to learn and perfect in Martial Arts like Tae Kwon Do or Karate. Here is an easy drill that can help you perfect your TKD side kick.
1 - Stand Straight and perpendicular to a wall
2 - Put your closer hand on the wall for balance
3 - "Chamber" your far leg -- no rotation or twisting yet
4 - Pivot your base foot and rotate your hips
5 - Extend your foot straight out, slowly, to complete the side kick
6 - Pay attention to your foot position
7 - Re-Chamber and straighten out your body
8 - Repeat until fatigue prohibits good technique.