I have found that sneaking up on the fruit bowl with a vacuum cleaner, then turning it on suddenly as the flies start to take wing, seems to help thin the population down a bit.
I've also tried letting a 'sacrificial fruit' sit out at the other end of the kitchen (I use one that is already bruised or badly messed up) in hopes that the fruit flies will go lay their eggs *there* instead of on my good fruit. I am not positive that it helps, but think it might.
The biggest thing I've learned is that once I've got fruit flies in the house, new fruit gets stored in another room, and the old (fruit fly-ey) fruit gets inspected daily and Something Done With suspicious ones.
You can buy pheromone-based traps, but I've never tried 'em.
Good luck,
Pat