I usually have 10 different animation projects going at a time.
Don't be afraid to look silly.
In general, I find that for videos the acting is more realistic.
I didn't record any additional dialogue for this CD, they are excerpts pulled from existing episodes.
Some shows, like PPG, tape in a group session, which is always more fun because you can play off each other.
Start as early as you can. Make tapes of your characters.