While I was writing the post about my watercolour from life, I thought about another type of art that is great fun. I remember sitting in Waterloo Station in London waiting for a train and I attempted to sketch people as they passed by. Obviously it required very fast and rough drawing as not every subject was standing still. I guess I took between 5 and 10 seconds for each sketch.
This is very useful as a library of ready-made people to populate a painting.
the way, don't forget that, as people (standing) appear in a drawing
further and further away, their heads all remain in a horizontal line
(assuming that you, the artist, are standing and looking horizontally). Their feet move, if
you see what I mean!