Bare minimum:
Common sense. Safety.
Build from there.
I look at it this way. The more people CCWing, the better off we are as a society. I think that once people are safe and familiar with their weapon, know the applicable laws, and have an understanding of the use of deadly force, they should carry.
I don't however think that they should stop there. Far from it. I think that anybody who carries a gun owes it to themselves to practice. And not just slow fire, twenty yard, paper punching. But lots of shooting, every kind you can think of. Seek out good training as much as you can afford it. Shoot competition. Any kind of competition. The more lead you put down range, the better.
I think that there is some great advice in the book StressFire. Make sure that something rides on every shot. Don't just screw around when you shoot. Even your plinking sessions should be usefull. Shoot under stress, bet your friends that you can out shoot them. Put some money on it.
As far as some basic skill sets, I've seen a lot of shooters who can't draw and acquire a target with any sort of speed. I think that Gomez has a point. Practice on close and fast a lot. Accurate is great, but accurate and slow is bad.
I've taught quite a few people to shoot. (not a professional, just that everybody I know comes to know me as the neighborhood gunnut, so when they decide to buy a gun, or CCW they talk to me). I've seen far to many new folks get really frustrated as they try to shoot pretty little groups from a bench. Thats not a very realistic indicator of what they are going to face in real life, and it tends to frustrate the shooter, and make them doubt their ability. The more they doubt their ability, the more confidence they will lose.
Enough rambling from me. This is an interesting topic.