A mic, some text, and a big imagination. More than enough to bring projects to life, but a recent client was nice enough to send me the full video that I would be voicing for reference, and what a difference it made. The job specs and my dialogue with the client set the right path initially, but having the actual video gave me a unique window into the rest of their creative process. I immediately was able to connect with the company and their product in a much more intimate fashion. I even wanted to start using their service. (wtg marketing!)
All of this is to say, reference material is PRICELESS. We don't always get it as Voice Actors, but in the wisdom of casting director, Andrea Toyias: if you don't have a picture of your character... go find one.
While Andrea was specifically referring to auditioning for characters in video games, I think it applies across the board. Find materials that put you in the world of your clients and their creative team. Character photos or company branding... if it inspires you and gets you closer to the project, I'd count that a win.
So off I go. Auditions are in, and I have some research to do!
... Or maybe I'll just work "Free Stock Photo banana guy" into whatever I get: