Yes, know the arc of the character you’re playing and the story you’re trying to tell. If for nothing else, information.
However, under no circumstances whatsoever, should you “arc” your performance.
We didn’t pay to watch you warm up, ease into it, modulate, pre-shape, know where you’re going, etc…Banish all thoughts such as “My character wouldn’t be that (insert emotion) here.”
Always, always start in the middle. Come out of the gates swinging. Go right for the jugular. Grab hold of us and don’t let go.
There are no limits on far you can go. Surprise yourself! Remember, just like in life, you have no idea what’s next or if there’s even another line coming. This might be it. Your only chance to change the other person.
So give it all you got. Now! Now! Now!