I have also begun supplementing my training with BJJ. The most important thing I have learned so far is in three parts. Defensive positioning - to be able to defend from others' techniques, offensive positioning - to be able to use a technique effectively without being put back on the defensive or being thrown off, etc (both positions offensive/defensive have much to do with your base), and the third is technique. It is great to know how to throw a technique in, but it is formidable to be able to maintain your advantage while applying your technique. Stay engaged with your opponent and the tactical positioning will be felt - and remember the more time spent on the mat rolling, the more experience you will have to experiment with the different positions, you won't know it until you get to use/feel it. Oh, and one more thing, don't be afraid to lose, I lose plenty and I say that I learn 10 times more when I lose than when I win.
Be well.
Farang - Larry