With the same discipline and attention to detail you would apply to any other instrument, you can excel in harmonica. Part 1 of this series covers how to choose a harmonica.
The harmonica is one instrument that lends itself well to self-instruction. We have found several harmonica books available that will be useful to the self-instructed beginner.
You Can Teach Yourself Harmonica by George Heaps-Nelson and Barbara McClintock Koehler (Mel Bay Publications, Inc., 1989) should probably be the first one you work through. It has care tips, technical advice, and plenty of fiddle tunes and blues songs to get you started. By the time you’ve finished, you should have all the basic skills you need to play harmonica.
After completing a basic-skills book, you’ll need to decide which style of harmonica playing to pursue. If you want to go the blues route, you will find Building Harmonica Technique by David Barrett an invaluable resource. The title says it all. This is not a songbook, but a book designed to improve your technique. There is also plenty of theory and application so that you can improvise a solo to any blues song you ever come across. Even if you aren’t really interested in blues, there’s a lot you can get out of it.
If you prefer to go the country/bluegrass route, try Bluegrass Harmonica by Mike Stevens (Centerstream Publications, 1997), which offers technical advice as well as some bluegrass standards and not-so-standards. And if your harmonica ever goes out of tune from age and use, instructions for remedying the situation are provided.