The CoD is great if you can get/have them, I would suggest doing those first.
Kind of on the same thought as Anthony, is lately I have been picking out sections from various labs and doing them back to back.
For example, my QoS has been hurting, so I have been going through each lab and doing just the QoS, studying what I miss and really focusing on the one topic, and I find it works termendously. After a week straight of that, I don't even flinch at silly QoS :P