If you really want to learn rolling circles, then plan on spending time practicing on a simulator. You can spend several hours a week for a year before you get the hang of it. You need to learn to use the rudder independently of the other controls. One good way to practice this is slow rolls. If you can coordinate rudder and elevator so that you can do single slow rolls the length of the flying field, then rolling circles will come easily. Following is a book I found useful about Advanced Aerobatics in general, and they have some other books leading up to this one:

http://www.rcflightschool.com/Adv_Manual.asp