Whats the best way to gain a horse's trust and repsect?

I work at a little pony ride place, and the little ponies listen to me, but they dont respect me. Two in particular, Susie, A big shetland, and Buddy, a Paint Pony, seem to have issues with me. I've tried messaging their ears and rubbing their necks softly and giving them treats when i can. Susie attacks me when i go to catch her, and Buddy trots away, and seldom kicks at me. I've heard contering them in a round ring until they make chewing gestures and letting THEM go to you would help, but the problem if We have a limited amount of space and money, and we dont have a round ring, or the means to build one..