What advice do you have for someone who is teaching himself to play the banjo?
well side note, there is no need to do this. you CAN of course. the problem is, it takes a lot more time to do it that way. someone that knows what they are doing can show you one thing that will safe you decades of time. but nonetheless here you go: a.figure out how to make a good sound with your hands. try to play every note on your banjo where it makes a good long sound. clear. b. get your chords and scales together. c. a good idea is to learn some vernacular styled music. one reason is, you don't have to ALSO learn/create/find the music you are trying to play as you are figuring out how to play a banjo and you can just PLAY. that way you are only doing one thing not two. there are tons of resources for this. d. record yourself and see if you can make a good sound. e. the two basic ideas are melody and rhythm chords. at first you might try to be really clear about which of these you are doing.
hope that helps!