Order of Study
Is it better to just run through all of Level 1, then go to Level 2, etc, or to do a few levels of each category at a time?
I'm not sure about you, but it takes me at least a half dozen to a dozen exposures to the target word before I remember it. Some words come quicker than others while others take me forever.
Just remember to have fun and take breaks a few days off from studying here and there. Allowing the information to soak into that great big sponge of yours.
Good luck, with your studies!