Playing Fullback in Rugby

I played full back for my school for many years and later at club level (not very high standard). I always found the best way to learn things like positional play was to watch the pros and study videos. I'm from England so I would suggest a video of a game with say Josh Lewsey in, he always had good technique in all that he did. But, of course, unless you're very good don't expect to emulate a very experienced international !