Eyes

Eyes can tell the audience a lot about what the character is feeling and thinking.

Darts: small little movements without blinking. Eyes hardly ever stick to a spot and not move, use it to give life to the character. Use the darts to lead into another eye direction. Darting back and forth in one small space can show rapid thoughts. Think about spacing in timing.

Blinks: aside from adding a blink when looking in a different direction, use blink to show thought. Rapid blinks mean something different to slow blinks. Read this EXCELLENT post by Shawn Kelly about blinks here

I mostly use stepped tangent. Always make sure that when the character is looking at something or someone, they are actually looking at them. Weird eye direction confuses the scene and the character's intention. Makes them look blind or stupid or like they're not paying attention.