Rule #72 - Studies have shown that women have a more developed sense of smell. Breath mints - small cost, big yield.

Breath mints and cologne are good, but personally I think most pheromone products out there are scams. With that said, if they give you more confidence due to a placebo effect, then perhaps they are worth the money after all. Not that I would endorse any, of course.
Smart Dating Rule: Have good breath.