My top tip: Be quiet, and no lights at night!
As obvious as it sounds, the tiniest, quietest footstep will carry vibrations into the water. All the sounds that you make will be amplified through the water within the stillness of night and these sounds will spook your fish every time.
Strangely, you’ll be amazed at how well you can see in the dark if you haven’t used a torch or light and allowed your eyes to become accustomed to the gloom. Make sure you arrive before darkness descends, look round and make a mental note of where everything is around you, this will aid casting, netting, etc. and all with the minimum number of snags, tangles, etc.
If you do need to rehook, or change tackle, you can generally see well enough to do this, slowly! If not, and if you really have to use a light, move away and face away from the water. Use a soft light, an old worn out battery in the torch will do the trick and do not turn around, strange moving light on the water will again, spook your fish.