Obtain the client's approval on the content and script of the radio spot before beginning production. Practice the spot without recording to make sure it fits the allotted radio spot length of time.
Locate a quiet space with as little ambient noise as possible. Turn off phones for uninterrupted recording. Set up the recording space in a room that will not echo. Be in a place that will absorb sound. Avoid empty rooms where sound waves will bounce back and forth and create echoes.
To achieve radio-quality sound, set up a professional condenser microphone, a preamplifier, and an audio interface (firewire or USB). If the computer has a broadcast-quality sound card, it is possible to connect the preamp to the computer line-in without the interface.
Record the dialogue, sound effects and royalty-free music into audio editing software such as Logic Pro, Garage Band or Sound Forge.
Take your bits of music, speech and sound effects and edit them together. In general radio spots are either 30 or 60 seconds long.
Convert the final product into an mp3 file. If the audio-editing software doesn't allow this file extension, then use a converter such as iTunes. Deliver the finished product to the radio station by emailing the mp3 file. If the file is too large for email, burn a CD.