A brief snippet:
For people who seriously want to get into voiceover acting, clearly the most important thing is that you must be a good actor. That comes first. That’s why celebrities get so much work in voiceovers – we’ve seen their work, we know they’re good actors. So take acting classes. Then take voice acting classes – and there is a difference. There are techniques specific to voice acting that you must learn. Not popping your Ps and how to stay on-microphone, especially during the physical scenes, and how to create the impact sounds. Getting punched and throwing a punch are two different sounds. Sneezing, burping, whistling and kissing all require silly little tricks. These are very specific techniques, and all are taught in voiceover classes.
Once you feel very secure in your acting and voiceover techniques, put together a voiceover demo – and only showcase your best work. Include things that are novel and new. If you do impressions, great, but let it be an impression that’s unusual and different. We don’t need to hear John Wayne. Include examples of accents, dialects, singing, singing in character, character voices. And you don’t have to be massively versatile if you have an interesting voice and you’re a good actor. Sterling Holloway and Ben Stein are good examples of people with interesting voices. But you do need to be able to act through your interesting voice. Finally, once you’ve put together your demo, you need to get it to all the agents and casting people and animation companies in town. Follow-up and keep following up, and hopefully somebody bites.