Unintentional canopy relative work kills. Mid-air collisions are always potentially fatal. They are particularly hazardous in low pull situations. Always track or dive away from people, into clear air and pull. Always give a wave-off and remember that the low man has the right of way.
Unless low altitude is a more serious problem, continue flying to avoid a collision. If you've already pulled and there are other people in your immediate vicinity, keep flying hard as long as you can before line stretch.
Develop and practice a dive-turn, barrel roll or loop that will fly you around an obstacle. You must miss the other person's body, if at all possible.
Be prepared to fend off another's deploying canopy. If you should get hit by a deploying pilot chute or bag, quickly knock it to one side as you fall off toward the other side.
Be prepared to use risers to avoid traffic right after opening. When surging together, veer to the right to avoid a head-on collision.
If you get involved in an entanglement, it can be nice if you've remembered your hook knife. It should be accessible to either hand, and you should be able to deploy it in one second flat, in a ready to cut position. However, before cutting loose from an entanglement, be sure to check canopies and altitude. Execute your pre-planned procedure(s) after discussing it with your tangle-partner. Generally, the lower jumper gets the honors of cutting away first.
If you're too low to cut-a-way, assess the survival potential of either riding it in or pulling your reserve. Of course, do whatever you can to assist the other's survival.
Be calm. Communicate. Act on a good plan quickly. If all else fails, head for the trees.
Be ready to do a first class PLF to hit the ground harder than it's going to hit you!