Expressions are a vital piece of information that can tell you how a person is feeling, what they want to emphasize, and how they want you to react to them in return. A great deal of information and experience can be gleaned from observing people. Your best examples will be people who are relaxed and comfortable sharing expressions with you. Translating these details to paper takes a matter of perspective and a few tips. Once you know the basics, the rest of the drawing is just practice.
Have these tools handy:
Practice pad of paper (this can be anything from printer paper to professional sketching paper)
Music, ambient noise, scented candles, or silence—whatever helps you stay relaxed and focused.
Set yourself up at a place where you will be comfortable and that has a hard, flat surface, such as a table or a desk. Also make sure to give yourself adequate lighting. Once you're comfortable, you're ready to begin.