Christopher, I have been doing minor repairs for years, and have a graveyard of cameras and lenses that I broke in the process. Living in Philadelphia is rich territory for buying used cameras and I have bought many a 5 dollar SLR that had only gummed up gears that were easily cleaned with lighter fluid.
But, start with either simple rangefinders, or prime, cheap lenses. Some lenses are rather easy to take apart and get rid of all the dried out lubricant on the helical so it will focus easier. Usually, one begins with the front by either unscrewing the center ring or, on some, the whole front of the lens body screws off. It is very frustrating but can be very rewarding even after you have (yes) KILLED hundreds of cameras and lenses in order to get down the knowledge. But do not throw out the dead bodies, they can be like gold when you need parts.
In a tiny container (like a plastic, screw-on coin tube from numismatists) you begin collecting tiny screws of all different sizes. These, also are like gold when you need them. I never bought a spanner wrench but use a sharp, old pair of scissors to unscrew the spanner nuts. What is REALLY frustrating is when some screws (most are NOT) are threaded to turn the opposite way (clockwise) to unloosen. I could tell you more but it's difficult to impart because each camera is different. If you email me I will send you my repair sheet. Also, from the late 70s to the early eighties MODERN PHOTOGRAPHY published, in each issue, an exploded view of a specific SLR. I am sure that you have access to a library that would have these issues on microfilm.
Minature screwdrivers are essential and I bought mine at the dollar store. - David Lyga email: firstname.lastname@example.org