Something that's worth mentioning is that how you learn affects how you can play. Sounds obvious, right? Well think about it.
I've seen a guy who can play banjo pieces learnt from tabs really well just go to pieces in a jam. No idea when chords change or how to improvise.
I've seem a guy who can sing and strum chords and entertain brilliantly on a guitar, yet can't tell that his bottom tenor banjo string is horribly sharp when fretted, to the point where it ruins the piece.
I play regularly with a guy who has no real idea what a key is, or that the capo is essentially just changing the key. Great singer/entertainer though. Until drunk. Did I mention that most musicians are hardcore lefties? As the old joke goes- "So you wanna be a musician? Well sign on, you crazy diamond!"
I've seen know-it-alls in a folk session get all technical to a beginner about a certain piece because it's in a different mode, which is common in folk. Ohh, it sounds sooooo modal! Don't get technical you douche, no newbie needs to know exactly what A mixolydian is yet. Just tell them to use the notes from the scale of D but use A a bit more, then they'll work it out.
Also I've seen folk players who are good in the common keys sit out a tune because the pipes are playing in F. If you take time to learn the basic scales you'll do yourself a huge favour. Once you've learnt one, learn the next one that is the same as the one you know, but with another sharp. So then you can always relate one to another. Example- G is like C, but with a sharp F note. This might be a bit unconventional, I don't know? All I know is that F is like C but with a flat B.
A basic knowledge of music theory is really helpful. There's a great app called Musicopoulis which a lot of music students use. Those with a basic knowledge of theory are much better equipped to rebuff other people who can play acceptably, but insist upon doing dumb things like tuning their guitar by ear with itself for a jam session, without knowing what intonation is on a in instrument. Or indeed insisting that others are out of tune, when they have inadvertently set their tuner to 448hz A or some stupid shit. Point is, a little bit of theory goes a long way. Just don't be a douche about it.
If you want to jam with people then you should start doing so. If you want to play in a folk session, then you need to go to some. What you mustn't do is sit in your bedroom until it's perfect. Because it never will be to your mind, and your idea of perfect may not quite fit when you're in a jam or session. Jamming with others will help you 'get your ear in' that much quicker.
Playing with others is one of the best things about music. Newbies should be encouraged to get stuck in. The human mind learns best by making mistakes. This is why kids learn so well- they're not afraid to make mistakes.
I'm by no means an expert, but if anyone has any basic questions then fire away.
If anyone has any tips for 'getting' clawhammer banjo then that's a style I'd like to learn.