Main thing would be to do some market research to find out what is ACTUALLY keeping people from diving, and what will motivate them.
The second phase of the research I did tested a fairly standard "Adventure" message against a different message I'll call "Possibilities" with non-divers. The differences in terms of the impression non-divers get about diving from these two different messages is quite interesting. I would say "surprising" but it's not really, as far as I'm concerned.
The purpose of the research was not to see if this specific alternate message is "the right answer" but simply to find whether varying the message can change people's impression of diving. In the research 219 non-divers were each randomized to one of two different groups. One group saw a message about diving that was focused on the adventure of diving. The other group saw a message that did not emphasize "adventure." Both groups were then asked to rate their perception of the accuracy of a series of statements describing diving.
For instance, a message that emphasized "Adventure" has a tendency to convey "danger" to non-divers more than a message that does NOT emphasize adventure:
Read this chart in terms of "percent of people who REJECT the idea that diving is dangerous" (So more people who saw a message that did not emphasize adventure REJECTED the idea that scuba diving is dangerous.)
And this difference was even more pronounced when you look at subgroups of people within each group. (For instance, the gap is even wider for people with an income >$50k. And take a look at skiers and golfers for something interesting.)