In a briefing something to keep in mind is that your New patient visits OR Initial Visit will always require 3 of 3 components & your Established patient visits OR Subsequent visits will always require 2 of 3 components. As mentioned E/M is one of those areas that require a lot of practice before you can become comfortable in coding it. Practice does make perfect!
Kathy provided very helpful references. Also if it's in your budget E/M university have a very basic E/M course for $19.95... It covers pretty much everything that you will need to know as far as the 3 main components go (History, Exam, MDM).