Sketching people is an important part building up your artistic skills. Top artists are always drawing people, they draw their friends, work collegues, family, models, people in a restaurant, etc, etc.
Lots of artists sketch people they meet and see on their travels. A good idea is to carry a sketchbook everywhere you go, then simply start sketching people!
So, what is a sketch?
A sketch is
a way of practising your artistic skills in drawing
an experimentary drawing – looking at how something works, it's almost like a rough description of what you see before you.
Sketches do not need to contain great detail. A sketch may be real or imagined.
It is almost like doing a quick study of something and while studying it, you jot down a quick report!
Why sketch people?
Sketching dramatically enhances your basic art skills. Regular sketching of people will bring a fluid style to your work, you will become more confident.
When you master how to sketch people, you will be able to produce a finished artwork without relying on a reference photo.