I'm not really in the mood for being too generous right now, so please first try doing a basic search on Google.
edit: Nevermind, I decided to cave in... I think that I need more a backbone.
Fashion was becoming a lot more disposable and easy to make and buy during the sixties. Plastic was being used a lot in jewelry. The shapes were bold, geometric and sometimes rounded, especially in terms of earrings. I've noticed that it was generally oversized and meant to stand out and be bold, like the rest of your outfit.
Of course, it depends on what type of person you were during the sixties. I'm mostly interested in the mods, and really couldn't care less about the hippies and whomever else, so you'll have to ask someone else, if that's the style you're looking for. In terms of that particular group though, there's loads of information out there, in terms of jewelry, fashion and basically anything you could possibly ever care about. Please, please just do a search! Really though, accessories in the mod style are incredibly easy to find, thanks to their revival around that Marc Jacobs period. Your everyday, "hip" fashion-y stores should carry similar stuff. As I said, go bold, chunky and head towards the bright colours. Even like, Claire's, has things for maybe five bucks that can get passed off as that period.
A general page on sixties fashions.
http://www.sixtiescity.com/Fashion/Fashion.htm
Some pictures for you...
http://www.sixtiescity.velnet.com/Fash2/Fashion2.htm
I've just been looking up some vintage clothing website though and they're not really the best out there, sorry... Try some other outlets as well, like ebay maybe. I'm fairly sure that we also have a topic on good vintage sites that you could use for inspiration.
These cost me perhaps two dollars at most.