Eezyreeder Harp Helps Page
Here is a guide to playing blues on a chromatic harmonica.
Here is my guide regarding kinds of harmonicas, keys, etc.
Here is a very useful article from Seydel for new players on harp response. Often the problem is not the harp --it is the player!
Here is an excellent chart on Harp Key, Position, and Song Key
Adam Gussow also has a fine YouTube video lesson on the two hole draw.