Okay, I'm copy and pasting this from another post, so sorry if some of it doesn't make sense. I just didn't want to retype it all lol.
It depends on what you want to do. Some people like to train with verbal commands. I personally don't because when you're in the arena, the judge is watching you closely and the more effortless you make it seem, the better. If you tell your horse to "Set" and the judge knows you did and the horse doesn't do it, you're SOL. Again, always try to have the same body language. If you're aware of it at first, then eventually it'll become second nature and you won't have to watch for it later. I stand at a 45 degree angle to the horse's shoulder. Point your boots at her shoulder, basically. Pretend there's a line drawn directly under her nose, and that's where you put your toes. It's alright to start the training by moving her feet with your hands, but after a while you'll need to quit doing that because you can't touch your horse in showmanship. In a HALTER class, you can, but your horse is being judged on his confo in a halter class. I've read that you should try to walk a horse forward to set him up, but I've never actually been able to get that to work. Supposedly if your horse has bad confo it helps to walk him forward rather than back him up but I struggle with that, so I usually just back my mare up. It doesn't matter if you set up the hind or the front first, just be consistent. Again, the pros say you should do the front first, I think... But as long as whatever you do, that's how you always do it, it shouldn't matter. I do the back first because I find that the hardest. So you get into your position, and say set... if you want to. To make your horse move a left hoof, tip his nose to the right. That takes some weight off it, and tells him which side you want. And vice versa for the other way. Look at the hoof you want him to move. I don't know why, but that helps. If your horse is young, just get it as close as you can. However, if your horse is old enough to focus for longer, accept nothing but perfection. If you let him get away with only setting up correctly sometimes, he probably won't do it in the show ring. Once the back is set up, do the front. It'll take a while, but like shesinthebarn said, whenever you get a chance, do it. As soon as the horse does it right, release all pressure again, and let him think. The key is letting them realize that if they are standing square you'll leave him alone. Square him up before you feed him. Before you let him go. Before you saddle, before you bridle, after you groom, when you get in the trailer, when you get out of the trailer. Do it EVERYWHERE. Then he learns that he can stand square anywhere, and that when he's square, he DOES NOT move. Then when you're in the ring and you're stepping around him while the judge inspects, he won't move. Once when I was showing a banner on the rail came off, because it was super windy. It was right behind the lineup of horses, and they freaked out. I had just set my horse up for inspection and while the judge tried to regain order (there were horses bolting and rearing. I was amazed that no one could control their horses in such a situation...) my mare and I didn't move. She was scared, but she'd been trained that when she was squared up, she wasn't allowed to move, so she didn't. We won the class, haha. But the point is, show your boy that when he's square, he can't move until you say. And repetition is the key. Shesinthebarn is right, the more you do it, the better you get!
Read more: Pivot
Anyway... If Lacey is more ruled by her stomach, you might try keeping a treat in your pocket and rewarding her with that. That's what my mare did, too, for the longest time. Maybe it's a mare thing! Ha, but it just took repetition and making her do it right. I just made her keep moving that leg that was ALWAYS out of position back and forth until she got tired of it and just did it. It's not that they don't understand, it's just that she doesn't think she should have to do it. Good luck! I hope I helped...