Most of us got our start hanging out with mechanics and car guys, when we
were younger. We worked on our own cars and made every mistake in the
book - or most every one. We simply do not admit to those mistakes any
longer...
Take your car to a smaller garage - one with a good reputation. The bench
rate will be expensive, but usually lower than dealerships and larger
garages. A smaller shop is more likely to let you hang with the mechanic
while he looks at the car, and you can explain to him that you're trying to
learn a bit. If he's a decent Joe, he'll explain some things to you as he
works.
Forums like this are good places to learn, but topics are scattered and not
organized into any coherent flow. You just kind of pick up general
knowledge to put into your hip pocket most of the time. That all by itself
is quite useful, but it also requires you have some idea how automobile
systems work in the first place, in order for it to be very meaningful.
There's lots of forums out there, so lurk around in many.