Ken just said a mouthfull.. Morning drive or afternoon drive. A testimonial from a trusted on air personality is good. You have to be willing to commit to a campaign for a while.. What are the demographics of the station? You don't want to advertise to 18 year old guys who are listening while they install new neon lights on their car. How big is the listenership? The better the station, the more expensive the ads. You could spend a year advertising on the wrong station and not get a nibble.
Find out what personalities the women like. See if you can work a testimonial out of them. I'm about to start my radio campaign. I am starting with one show that has a regular listener base. I am getting the on air personality to do a testimonial for me. He has seen our work at our church, his home, and the radio station. As I can afford it, I am going to add other time slots. It is nothing to drop ten grand a month on some stations, or even MUCH more.