1. Stay Consistent. According to the teacher that I studied under at Acting Studio Chicago, Dave Leffel, this is the number one "rule" of voiceover performance. If you start off with a high energy voice you need to be sure that you're maintaining that voice for the duration of the spot. This can be challenging, especially if it's 30 seconds of overly written copy.
2. Research. You need to know what's out there. Have a habit of skipping over commercials? Stop that. It's research built into your leisure time. Actively listen to what's going on, what kind of sound certain advertisers are interested in. Does McDonald's have a certain sound? What about Plato's Closet? Start trying to determine where your voice fits in. Be honest.
3. Stay you. I know it's hard, especially after you've done lots of research and know the products that you'd like to pitch and the voices that are used for said products, but don't do impersonations of the voices you hear on the radio. Use your own unique voice.
