I think by seeing more and more riders out there riding with gear and example will be set, just as cecil said.

Lately I've been seeing more and more people wearing helmets, even those on cruisers. Collectively I think Tampa has some smart riders (drivers of vehicles can be said to be otherwise) but this is the hot season for bike sales and thus your going to have alot more new riders.

If the local riders could organize a biannual ride where it is a pre-requisite to wear gear and possibly in the near future organize something resembling "trade-shows" for gear manufacturers I think that would also help. However as Matt said, your not going to be able to weed out all the morons that must be left up to social-darwinism.