If you've emailed or called me recently and I've ignored you, it's because I don't like talking to strangers. Nothing personal.
Well, it's more because "Can you tell me about voiceover?" is a big, vague question that I'm getting asked more and more, and it's very hard to answer concisely. I usually don't answer because the answer's too big to get into. So instead, here's a list of numbers with stuff next to them that I came up with:
#1: It's a business. Do you know how to run a business? Learn. Make a website, make profiles on VO sites, get testimonials, maintain a blog, etc. Do it all until you get results. Then keep doing it. But remember, this also means creating a legal entity, keeping books, building an invoice system, marketing your ass off, paying an ungodly amount of money in taxes, should you be so lucky.
#2: You're selling you. You're a salesman. Your product is your voice, and probably the delivery method for creating the audio file of your voice. Learn all the necessary skills to make this product. Go to market with this product. This is your job. Recording a job in a booth is a benefit to this job. You also includes your gear, so also be prepared to get into audio gear, a lifelong obsession.
#3: If your product sucks, it will fail. Your product (voice) should be good, meaning that it solves the casting agent's/casting director's/client's problem. Figure out what that means and then deliver it. There are a million books and blogs on the subject. Read them. Practice. What is it, 40,000 hours before you're really good at something? Get going on that.
#4: Knowing your limitations is great, but don't limit your options. I do audiobooks, commercials, cartoons, podcasts, video games, industrials, corporate training videos, museum tours, corporate retreat openers, toys, medical simulations, wearable apps, documentaries, film trailers, and whatever else people start needing voiceover for (in addition to live and on-camera acting, singing, writing and performing music, audio engineering, and modeling). Since I'm near their campuses, I run into people who take classes at Edge Studio, and I hate how much they harp on 'niches' and how VO's should focus on one. It's a bad way to go. (Also, everyone who's trained at Edge reads exactly the same way. Also bad.) Learn how to perform, study acting, and you can do any kind of voice over work. It helps to be a musician, perform theatre and improv; to record, edit, and mix audio like a professional is also pretty crucial.
This isn't a side gig. It's full time or you will probably not do well enough at it to maintain your interest in it. I recorded two gigs this week and I'm bored as hell, but that mostly means I'm doing more marketing instead. It's a lifestyle choice more than a job. You need to be able to commit to it.
There's work out there, I know that much. You just have to find it, convince the client you're the best one to do it, do the job, and get paid. Do that a ton for a long time for a lot of different people and you'll be a voice actor.