Agreed, buy something to tinker with, I'd suggest getting a car that you can use on a track so you will always be developing it and things like fitting brakes and suspension will give you a good insight into how it all goes together. It'll be more of a project. I did the same thing when I was younger with a drag racing V8 Targa Opel Manta, taught me so many things about cars that I still use today.
Another option would be to help someone who knows what they are doing already, be a spanner man for a hobby before taking something on or enroll in a college course, most do a mechanics course.
You will only get better by doing as much work yourself as possible, I do know some people who think they can work on cars and always end up bringing them to me to finish or fix, I think some are cut out for it and others aren't.