Physical readiness. As in, being in shape....
This was my first thought also. If you can't do 50 push-ups, 100 sit-ups, and run an 8 minute mile, you better be on the good side of several people who can. Also, if you're on maintenance medications, what happens at the end of the month when they're all gone?
After basic health and fitness, next you need the ability to hide. The grocery stores only have a two day supply of food. Once that is gone, the locust will swarm out of the cities. If you live in an urban or suburban area, the only way to survive the onslaught is if they pass you by. Hide. Do you really want to kill several hundred or thousand people to protect your 3 - 6 month supply of food? Do you think you can? They may just kill you first.
Those with "bug-out" plans: given the effect of a few finder benders on rush hour, do you really think you're going anywhere during a full fledged panic?
Best skills? Health maintenance, fitness, camouflage, hording/stockpiling, collaboration with like minded people, basic firearms skills.
I live on a peninsula. We'll just block the road at several places, and covertly guard the narrowest point. It necks down to less than 100 yards, with clear fields of fire - but it's best if no one ever feels the need to walk down the road. MSG