This is a little something I've been doing for the last few series I've watched. As you go through and are watching whatever anime interests you, pause and take a screenshot if you see a face shot of character like the one like this one.
A few rules that I follow are.
1. The character has to be looking directly at the "camera"
2. No side shots or angles. Full frontal portrait.
3. Try to keep only their head in the shot. Shoulders are fine, but the best ones are of just the face.
Anyway, here are some more examples.
Best of luck and have fun.
note from moderator: I've left all four examples in to give a good sense of what's intended. In your own response posts, please post only one image.