If riding lessons are out of the question for whatever reason, make an attempt to find someone in your area that knows something about horses. Most horse people will gladly share their knowledge about horses. You may go through several mentors over the ears as your knowledge increases, but they will be the best investment in time and money that you will ever spend.
If you don't want to find a mentor, or can't find one, you have a couple of choices. Books, are a good start, especially if you are someone that is good at reading a book and then applying that knowledge. There are also videos that you can buy or rent. There is a website that is like Netflix, which you can stream videos like the ones you buy from people like Clinton Anderson, Pat Parelli, and the like. There are also thousands of training videos on youtube, but be careful because there are some videos on there that will quickly lead you down the wrong road. Depending on your location and monitary situation, going to clinics is also a way to get access to knowledgeable horse people, I know that all of the ones that I've checked into, spectators are only charged like $25.00/day, and you can still ask question and get answers. They are a good way to be introduced to the world of horse training without having to buy a horse. And there is a huge variety of chilcians to choose from. I've seen a few of Clinton Anderson's videos, and he is brilliant at explaining how to do something, but I've also heard that he can be quite harsh and crass at those clinics. But that can also be because he tends to not sugar coat things, if someone is doing something wrong, he will quickly point it out. I personally would love to go watch Buck Brennamen, especially after watching his movie, "Buck" he seems to be a sincerely genuine person. And that seems to be a rarity these days.
Regardless of what route you choose to gain knowledge from; Trainer/Instructor, mentor, books, videos, or clinics; horse knowledge is something that never stops coming in, especially where training is concerned. And, since we are all trainers, we should never stop learning, ever. When we stop learning, we stop progressing in our relationship with our horses, and when you stop progressing, you might as well just sell out and move on.
Good luck, happy trails, stay safe, and God bless you and yours.
Until next time,