it helps to read books and check out online stuff like groups and forums, but if your interested in learning you need to get hands on experience. if you have any mechanic friends id hang out with them and help out. the more you spend time around problem machines the more you will see what solutions work and what dose not. i can recommend books on specific topics but not for general expertise. check out your local library if you can since thats free. i suppose you might not learn the same way i do of course but its hard to go wrong with real experience. if something in specific interests you you might check out yahoo groups and similar clubs for it as there are some brilliant minds there often.