Relaxed tension: Jiu jitsu is a physical game. People often pontificate about how size and don't matter and it's all about pure leverage etc etc. The fact is, you'll need of exertion to enter into and complete effective moves on a skilled opponent. We all have a tendency to go all in on exertion to a point where it becomes very counterproductive. The key is being able to manage tension appropriately. You don't want to be a rag doll – you'll never beat anyone that way. Nor do you want to be under continuous maximal tension, you'll quickly get exhausted after a strong and lose as time passes. The best athletes discern when they can lower tension to a level appropriate to the second by second they find themselves in. They also put a cap on how long they'll allow themselves to take their engine to the redline – too long and you'll overheat. The best visual to tension is the face. If your face is contorted with exertion for long periods of time and in situations where nothing is happening – something is wrong. The best athletes have a like calm to their face for the vast majority of the match – even in situations that are pretty intense. They reserve their redline energy for the few times it's really needed in a match try hard to follow this example. It can be difficult when starting but it's very important for your long term development