I record music which involves strong vocals and attention-grabbing mood, as well as variety in tone and pace. In voice acting, I talk the way I think the character would talk. In advertising or presentations, the idea being promoted is projected in such a way that either gives a proper feel for the product (such as advertising different video games or movies), or which depicts reliability in the idea (to "sell" the idea, if you will). I learned when I was in theater class in 9th grade, when trying different voices for different characters. When I graduated, I dubbed cartoons for fun, and eventually tried working on my own short films (based around video game characters).
The skill began when I did voice-overs to muted cartoons, in which I basically improvised new dialogue to an existing character or characters, and played around with voices and accents. I learned by listening closely to dialects spoken on radio and television, and I made a hip-hop album with skits doing voice talent. One skit I did in particular parodies Star Wars. I also received inspiration from professional voice talents Brad Dourif, Billy West, Mike Judge, David Hayter and Seth MacFarlane.
In my theater class, I had to do a project where I put together a "radio simulation". This was done by me sitting at the back of the room with my back towards the front, and the rest of the class facing away from me, in their neutral seats. I would then have to sell a performance with multiple voices and accents in order to either make them laugh, or grab their attention. It was succesful, and my grade was an "A". My teacher for that class was Keith Ingram (radio personality for Clovis, NM radio station KTQM/KWKA).