I'll give my input, though I'm not a practitioner of BJJ, so take what I say with a grain of salt. I think your best bet, outside of working on technique, would be to focus on explosiveness. Strength is important as well, but you want to be able to apply that strength in but a moment - thus, you need the ability to accelerate and create a lot of force.
Try to train in cycles, where you increase your strength capacity for some time, then switch over to training for power, all the while practicing your techniques for BJJ. Muscular endurance and cardiovascular ability will come from BJJ itself. You can throw in a little extra to help you along, but one thing you need to really focus on will be explosiveness. This will come through weight training, especially olympic lifts.
Flexibility may be important also.