How can I draw a variety of facial expressions for an anime boy?

Facial expressions are key in anime. To draw them, focus on changes in the eyes, eyebrows, and mouth. For happiness, widen the eyes and curve the mouth upwards. For anger, furrow the eyebrows and narrow the eyes. Surprise can be shown with wide-open eyes and an open mouth, often in an 'O' shape. Experiment with the slant of the eyebrows, the size of the pupils, and the curve of the mouth. Even subtle changes can convey a wide range of emotions.