Bottom line: The CD wants you to bring honesty to the role. How do we best do this? By bringing as much of ourselves as we can to the role. Doesn't matter if it's a comedy or a drama. The more of ourselves we bring, the less we have to "act."
But hey, we're actors - aren't we suppose to act? Well, yes and no. Unless we're playing ourselves, we're always going to be doing some acting, but pretending is never as strong as real, sincere emotion that comes from our heart. When you see someone act who really moves you, don't you feel like that actor must really feel that way about whatever it is they are reacting to?
Haven't you seen an actor doing a scene where he is supposed to be angry (or sad or scared, or another strong emotion) and you just don't buy it? Even if the acting isn't bad, you just feel like it's not "real"? And how about when you almost feel that the actor is really angry (or sad, etc.)?
That's usually because he (or she) is tapping into the angry part of themselves. They find that part of them that holds the "angry" emotions, and they let it out.
We all have those different emotions in us: anger, lust, sadness, fear, silliness, etc. The best actors find those emotions and allow the rest of us to see them. That's what holds back a lot of actors, because most of us have been raised to not show emotions - especially the undesirable ones like lust or anger. But in order to really make others feel what we're feeling, we must be willing to tap into those real parts of ourselves and show them to others.
That brings us to the "acting" stuff. Acting is really about using a real emotion (not acting) in a situation were you wouldn't feel that way (acting). For example, maybe you can really feel anger at people who hurt animals, but the scene calls for you to feel anger at your sister. You make the anger real, and act the part that it's toward your sister.
And this is one of the main things that casting directors (and directors) look for at an audition (and in a performance).
Ask me about other things a CD looks for - I'll be glad to help any way I can.