I have 2 suggestions.
1: Arm yourself with knowledge, read everything
watch every video you can find - of course take it ALL with a grain of salt. Watch and read everything, learn the things that ring true, forget the tings that don't. The more you know the better owner you can be.
2: Get a knowledgeable person to teach you. If you can't afford a trainer to help you and your horse specifically here's my best suggestion: Go to a rescue, tell them you want to learn all about training, volunteer there with all your free time. You will learn SO much. Spending time with experienced horse people, even if it's not a lesson you're still learning. You can also discuss with them what you're doing with your horse and get their opinions/ideas on it.
Here's a few VERY helpful links that I've used in my own training and working with my horses:
The first is my favorite, it's all about clicker training, and how to do it properly, so as not to create more problems. I love clicker training as it's simple and Positive! Video 1
This one is Clinton Anderson, he uses a Natural horsemanship method. I personally mix much of his methods with Clicker Training, as this helps make things easier for my horse.
This is Pat Parrelli (I'm really not a huge fan of his, but as with most trainers, he has some really great concepts) these games of his are fantastic for new horses - they're also a fun way to bond :) Horse Training Games - the Friendly Game
Good luck :) Welcome to the forum, we love pics here.
Also, I'm not sure what age you are, but regardless, you're working with a large, potentially dangerous animal (even if he's typically mild mannered) Always make sure someone knows where you are and can check on you regularly when you're with him. Accident's happen, even if he doesn't mean it, horses are large. So make sure someone is able to help in an emergency.