I am going to try and explain it as simple as possible, and if you have any questions feel free to message me!
The main parts to showmanship at the basic level are:
- backing up
For walking/trotting you want them to be enthusiastic and moving with cadence and rhythm. Have them in the proper position with you around their eye or farther towards their neck. Your lead should be fairly loose to show that your horse is listening more so to your body language than the actual lead shank.
When backing up and halting use your body language much like in the saddle. Pull slightly backwards with your hands (making sure they are up in riding position just as you do in the saddle). You when them to stand square and that takes time and practice, by simply moving them until they reach that point and rewarding graciously. Remember, when you back look past your horses hip and try to keep as straight as possible.
Push-turns, pull-turns, or pivots are one of the hard movements, but easy once you grasp them. You always want your horse to pivot on his inside hind foot. Just push the lead under his neck and if needed tap his shoulder until he moves from the pressure, but know that is only allowed during training and you can be disqualified for touching your horse at any time in the ring.
When showing, your attire should be neat and clean. Western-type is normally the stockier breeds and are normally shown in blingy leather halters and lead shanks. A Western show shirt and dark blue jeans would be appropriate with a helmet or hat if applicable. For the slimmer breeds (Thoroughbreds, Warmbloods, etc.) they tend to wear English show apparel (breeches, tall boots, hunt coats, etc.) and show in a nice snaffle bridle.
In general look alert and proud of your horse. You want to act like he/she is the best and they deserve that ribbon. Smile! Look towards the judge and remember your quarters to avoid obscuring their view of your wonderful animal!