The key to making smooth flying lead changes is to give just enough input to your horse to cue the change without interfering with his relaxation, balance, straightness and rhythm. Unfortunately, some riders try too hard to produce changes, swinging their bodies dramatically in the saddle, pulling on the reins, throwing their horses off balance and making them tense and anxious. As a result, the horses lose their rhythm, change late behind and miss changes altogether.
My three-step system for teaching flying changes consists of perfecting your canter departures, doing simple changes and then progressing to flying changes. My emphasis throughout is on relaxation and smoothness.
For more, read Jennifer's step-by-step article, "Take the Stress Out of Flying Changes," in the June 2010 issue of Practical Horseman magazine, and learn more tips and troubleshooting techniques.