Before we even had Cat 5, the system was designed to rely on Clubs/Teams to teach their new members.

I think the ideas in this thread such as clinincs, and seperate 5's races, are good, but are difficult for organizers.

Another answer is a greater emphasis on Clubs/Teams. If you go out and do the training rides with the local racers, find a Club/Team to learn from, you can learn a fair amount of what you need to know before you do your first actual race.

Increasing unaffiliated rider fees would help in this regard.

Arguably this could discourage new riders, but you could mitigate that effect by giving out information on hooking up with a club at the same time you collect the unafilliated rider fee.