Hey, I've been playing violin for 9 years. I know a few people who can fiddle up a storm, and what I've noticed about them is that they
1. know the instrument really well
2. can play by ear
3. have great violin technique in general
if you've never played violin (aka fiddle) at *all* and don't plan on taking fiddle/violin lessons
here are some suggestions:
a. Unless you have an incredible ear, make sure someone puts some tapes on the fingerboard (where you put your fingers) in the right place.
b. Get this book:
Essential Elements for Strings
We use it at the elementary school I help with and it has *great* tecnique and teaches you solid note reading too.
c. Pick up the violin for fun and start sounding things out. If you learn this early, you can go really far. still pay close attention to tecnique, though, because your sound can greatly improve with great tecnique.
d. Find some fiddle instruction books

) I'm not sure what to recommend.
I teach violin lessons. Email me for more!