I think of them in terms of packages.
A Superb Skill Package costs 15 skill points and gives you one Superb, one Great, one Good, one Fair, and one Average skill.
A Great Skill Package costs 10 skill points and gives you one Great, one Good, one Fair, and one Average skill.
A Good Skill Package costs 6 skill points and gives you one Good, one Fair, and one Average skill.
A Fair Skill Package costs 3 points and gives you one Fair and one Average Skill.
An Average skill costs one point.
It doesn't help so much for advancement (then I think of them as stacks), but for initial creation, I find it immensely useful.