In this clip from Alfie, Jude Law breaks the fourth wall, and his mental state jumps back and forth between deep thought and addressing the audience. Study the difference in the eyes as he moves between the two states. There’s some nice texture in the eye darts. For example there’s a moment that goes dart, dart, blink, dart, dart, but the darts before the blink are different from those after in both timing and spacing. Subtle stuff, but when the acting is this restrained, it really counts.
On the flip side, here’s a clip from the Tonight Show with guest Chris Pratt. Studying acting is great, but nothing beats a truly natural “performance”, and these interviews are always full of stuff to study. I especially like the Box of Lies segments. In this clip Chris Pratt is clearly fired up. With that in mind, watch his hands. There’s rarely a moment where they aren’t moving, even within a “pose”. I don’t know about you, but I wouldn’t have considered keeping the hands this active in a shot before watching this.
While this might not be directly applicable to your shots, as you’ll typically want to boil them down to what’s absolutely necessary, it’s great for observational purposes, and will be sure to ruin the Tonight Show for you from now on. 😀