Here's a little article I wrote about how to create consistency of characters in a feature film, and working in different styles of animation. This is something I'm dealing with a lot right now; the humans on Toy Story 3 are designed, and therefore animated, in a very naturalistic way. I couldn't animate a Toy Story human the same way I animate a Ratatouille human, for example. On Ratatouille the characters were a lot more stylized, so we could push their performances further and get pretty broad with them. On TS3, I find I'm relying on video reference a lot more, and having to work harder to get the mechanics and weight just right.
It's always important to listen to your director an supervisors, and pay attention to what other animators are doing with the characters.