I would recommend a few books.
A Twist of the Wrist I and II - Keith Code
Total Control - Lee Parks
You will find that riding effeciently is an equation. Riding form is definitely important, but it's just part of a whole bunch of other things you will need to work on. I am not good enough to advise you on how to improve, but I can point you in the direction others have pointed me. (i'm still really new to performance riding myself)
Also:
http://www.nesba.com
These guys are solid for helping and coaching. Some events can get a bit over-crowded (in my opinion) but if you seek help, you can still get it.
I, unfortunately, completely disagree with the claim that you should run what feels "right" and not work to get off your bike. I'm not trying to start a war - but there is very good reason to work on your "form" and get off the bike, besides the obvious coolness factor. It's simple physics really - but in summary, the farther you are off the bike the less lean angle you would need to negotiate a turn. I have heard people claim there is a bit of a turning effect created by the "sail" that your leg creates as well. Also, I've heard and seen people actually save a possible lowside becasue their leg was out there - at least it appeared that way.
Now - working on getting your knee down just for the sake of getting your knee down ;-)... i may not endorse that.. but congrats, it's the one thing I think most everyone remembers. I certainly do.