If you're really that interested in training yourself in voice acting before stepping into the realm, then there are training videos and courses available all around. A little guidance and training can take you a long way in this career.
Surf the internet to look for really helpful courses and mini-courses on voice-over jobs, voice acting, and how to crack your way into the business.
The more you spend (both time and money) on training and development, and just generally sharpening your skills, the more success you'll gain in the career!