Being young and poor helped me. Could barely afford the parts let alone paying someone to install them. Lots of wrenching, lots of learning the hard way, you just have to dive in and start somewhere. Like Stig said most products come with decent install instructions. Start small with a cold air intake or something along those lines, then you can progress to other things as well depending on your goals. Start doing all of your own maintenance when feasible. Stick with the bolt ons at first and when you feel more comfortable, then tackle a cam or something.
It's also great if you happen to know someone who wrenches, that can maybe spend an afternoon with you working on the car in trade for a case of beer or something! Guided help is great, you get to wrench yourself and hopefully your friend will keep you from doing anything dumb