Drawing people from the side is no different than drawing people from the front. The key points to remember are to start with a sketch of the basic shapes, and to pay attention to what the person actually looks like.
Take several photos of your subject. Choose your favorite and print it out or put it on your monitor to study.
Look at the basic head shape. Is the back of the skull more oval? More rounded? Look at the nose and jaw shape. They are part of their own oval shape. How far does that shape jut out from the skull? Think about the smaller parts that make up your subject's profile.
Sketch out these basic shapes with a pencil. Don't add details like eyes or lips yet. See this in yellow ink in the example.
Start to refine your basic shapes. Add your nose and chin. Smooth out the lines that form the basic skull, neck and shoulders. Remember that every line on the side of a person's face means something--it relates to the muscle and bones underneath. Think about the muscle and bones as you draw. See this in blue ink in the example.
Consider erasing some of your early pencil lines so you can see more clearly what you're doing. Be careful not to wrinkle your paper as you erase.
Add in more details--the eye, lips, ear and hair. Remember to always study your actual photo or person very carefully. This is the point when many people start to draw eyes and lips as they imagine them in their head. But you have to look and really see what's there and how it relates to the skull structure you already have.
Once you're satisfied with your drawing of your person from the side, erase the lines you don't want. Study your photo or actual person to see what shading you need. Typical places that might need shading are the eyelids, hair, shadows under the chin and slight shadows on different muscles in the cheek.
Pay close attention to your subject--don't draw from your imagination, draw from reality. Start with big loose lines--not small careful ones.