In my experience, what voiceover clients and potential clients want to know is*:
1. How do you sound?
2. How quickly can you turn their projects around?
3. Do you have a professional studio?
4. Will you deliver what they’ve asked for?
*My answers: 1. Warm, friendly, authentic 2. Most short projects within a few hours, 24-hours max; 3. Yes; 4. Yes, and, if it’s not quite right, I re-do it.