Organize a press kit that includes the following: the new artist's CD in a jewel case with a track listing, a one sheet detailing what you're sending to the station and why, and press clippings/quotes highlighting the new artist.
Submit your press kit to the music director at a radio station.
Call the music director two weeks after submitting your press kit. Ask her if she received the press kit, listened it it, as well as if and when she is going to add it to the rotation. If the music director says that the station will be playing the new artist's music, thank her and continue to follow-up for 6 to 8 weeks after with periodic phone calls.
Organize a group of supporters to contact the radio station and request that it play the new artist's music. Do not barrage the station with requests.
Contact a promotion agency, if possible. Submit your music to the agency. If the agency is interested in working with you, it will use its vast network of connections to submit the new artist's music to radio stations and work on getting its music played.