What I do is pretty simple. When I play a round with other players, I check to see if they're in a club. If not, I wait a few holes to see what kind of player they are and how they interact. If I like what I see, around the seventh or eighth hole I'll simply ask if they'd consider joining a CC. About 10% of the time I get a yes, and thus a new member.
I don't think the level of the club makes a helluva lot of difference. My club is level 11, but I've never had a "prospect" ask what level we are.