I taught Cuzco to stand the same way I train horses. I started by tying him to a fence post with about 18" of slack so he could move but couldn't get away. Then I would brush, bathe, trim feet, or harness him. Every time he moved away from me I would say "woah" firmly and give a tug on the rope just under his chin. As soon as he stood I would praise him, rub him, and give a treat. Once he was standing still while tied, I let the rope dangle on the ground and did the same thing. It didn't take him long to figure out what "woah" meant, and that if he stood quietly he would get a cookie. Af first I gave treats for short periods of standing still, then gradually lengthened the time until now I give him a treat only after I finish whatever I am doing. But I always give him a treat. Goats like to know you're going to make their good behavior worthwhile.
If you don't already have them, try to install some anchor points on your truck or trailer you can tie your goat(s) to. Even a well-trained goat may not stand properly if there's a strange dog at the trailhead, or if a bear came through the area the night before. I've found the anchor points on my truck bed and the grill guard to be invaluable when I've taken Cuzco to fairs and other public places where there is a lot of excitement and no hitching rail. In my case, I don't want onlookers watching me dance all over the fairgrounds trying to wrestle my goat into his harness and cart. No one wants to let their kids ride behind a bronco goat that was last seen dragging its owner across the parking lot! So having a good place to tie combined with a well-trained animal that knows what "woah!" means will make your life (and your goat's) much easier.