Good luck with learning the melodeon. It's a more flexible instrument than many give it credit for. You've got lots of good advice in this thread and I'd like to add another one: learn about music, i.e. learn how the notes in the scales relate to each other; learn what notes make what chords and try them out on the right hand; learn the 'syntax' of how scales and chords fit together. You won't regret it and it won't harm your folk credentials. All the top players these days have a good background in music theory. Also on the left hand, try 3 finger playing, with counter-basses, and learn about cross fingering to get chords like Am7, Bm7 or C9. This may sound like Martian at this stage, but in the long run will make your playing more interesting, especially on the slower tunes. Oh, and if you have a G/D box, which I suppose you have, try to find tunes that you can play in A (Cock of the North for example, but all the notes are pulls!).

Tradsinger