I'm doing some minor research as I go. Like pulling up google and a few pages, typically Wikipedia. Then I pop in the basics as a placeholder for more thorough information later. If I do too much research I get caught up in learning, then I lose my train of thought. :(
I tend to stick with what I know, but sometimes a character takes on a mind of it's own and all of a sudden I've typed that they know how to play the violin (which I know nothing about). Crazy things like that :P