Shaping is the term used for GRADUALLY lengthening or fine-tuning a response. ie: After your horse reilably backs up one step, start asking for two. When that is an easy task, ask for three etc. etc. Soon he will back clear across an arena with only the lightest pressure from the bit and your calves.
Shaping is a very gradual process. Whe your horse has accomplished one maneuver or portion of a maneuver with ease, you may ask for the next step. You can fine-tune his performance by baby steps until his routine is a work of art.
Shaping takes patience. If he shows any signs of confusion or poor performance at a new request, retreat to the step before his failure, re-work that step until he is again confident, and then progress again – backtracking if necessary and taking finer and finer pieces slowly but surely. If his confusion is too great, break the new maneuver into even smaller pieces or examine your equipment and timing to be sure he is understanding the cues.
(see Release Training)(see Bit Balance)(see Back Chaining)