That is a very broad question without specific answers. You have to remember that horses are herd/ prey animals, they flight or fight in response to a situation. The herd animal in them says look to your herd leader for guidance. You are supposed to be their herd leader when you are with them, so they should be looking to you for leadership and answers. As the herd leader you have the responsibility of teaching them to be respectful. A respectful horse will stay out of your space, stand quietly for grooming, back away when told, keep two eyes on you, lead quietly with you, go the speed and direction you want to go and the list goes on. Verses pushing into you, stepping on you, fidgeting when tied, pinning ears, turning their butt to you, bolting, spinning, dragging, nipping ect. Training is how you become a herd leader. You need to be able to control your horses five body parts, head and neck, forequarters, ribcage and hindquarters. When your horse knows you can control its feet then the problems of disrespect either don't happen or are easily fixed.
Horses are big animals with a very fast reaction time, reading about training them and actually getting your hands dirty training them are two different things. It is very easy to get into wreck with a horse in a matter of seconds, and get injured very badly or worse killed. The best way to learn to find a good instructor who is willing to teach you to be safe, and how to gain a horses respect. And you should be learning on a quiet calm horse to build confidence. I commend you for researching horse behavior learn all you can, but remember nothing takes the place of hands on experience. Good luck on your journey.