There are a lot of good suggestions above for you. One that I did not see was make friends with someone that does their own maintenance/has knowledge in the area. You can learn a lot form books and the interwebz but neither will hold a candle to working along side someone that knows what they are doing. If you have a friend that does his on work just ask him to let you know anytime he is working on his bike because you would like to observe and learn.

 

One of the best things you can do for yourself is make friends with someone that is in the business and knows what they are doing. When I got into bikes that's what I did. Brought my bike in for some suspension work and ended up with a part time job there. Fast forward 10 years I no longer work at the shop but I have full use of it and I break my bikes down to the frame and rebuild them every off season. The owner ended up being my best man at my wedding and I raced out of his shop and garage until this day.

If you don't have such a good option good space and note taking is key. You'll want to be able to spread out a little bit as you take things apart.

Get a digital camera to document where you came from so you can get back there.

I like to use ziplock bags to label non obvious parts like nuts and bolts as I take them off so I know where they go.

The internet is good for a resource but be careful. There is a lot of bad advice out there.