Harmonica Blessing No. 1 - No Wrong Notes (Lesson 1)
Your C Major Diatonic Harmonica only contains the notes of the C Major Scale... nothing else (unless you bend... which the harmonica was intended to do). You can play any note and still be staying away from "bad" notes. On top of that, even if you're going for a specific note and miss it, the note to the left and to the right of it are harmonies of what you meant to play... it still sounds great! This also means that if you can't even play a single note well... or you're just a little off on your aim... you're playing in harmony... two notes played together sound great... you literately can't go wrong! Thanks to Heir Richter for this wonderful harmonica design and note layout.
Now, let's get back to reality. This doesn't mean that someone with very little experience will play really nice sounding combinations of notes... they need to memorize licks from great players... but there are some more general thoughts that can help them out as well that we can go into.
When you start to play a lick at the beginning of the 12 bar blues progression, start with a draw note and see where it takes you... all draw notes match the I7 (the chord in the opening four bars). Mix blow notes in, but only as stepping stones (on your way to another draw note... make sure to not hold a blow note). When on the IV7 do the opposite.