If you're looking to establish solid basics in your lead change, be sure to pick up a copy of "Teach Your Horse to Change Leads" with experts Charlie Cole and Jason Martin, produced by gohorseshow.com. See a clip of the video below.
Check out Charlie's winning run aboard VS Code Red at the 2011 All American Quarter Horse Congress to see what truly spectacular lead changes look like in action. Notice the horse's position, timing, and pace come together to present a spectacular run.
For Charlie's lead-change refinement tips, pick up a copy of the June 2012 issue of Horse&Rider.