It was a cold day at a Starbucks when I drew this woman. She was all bundled up in a down jacket and cap, sipping a hot tea to stay warm inside this already warm coffeeshop. Never underestimate how Californians react to cold.
I find drawing caps an interesting challenge. The difficulty is the cap has two forces working at once, as the cap clings to the head in some spots and in other spots it is relaxed creating folds under its own weight. How you describe the shape and the line quality you use to show the differences. The top of the cap where there is no tension uses a more relaxed line, letting the eye feel the folds of the cloth, where the cap is pressing tight against the head is a harder line that conforms to the shape of the head.
Secondly showing how the cap moves around the forehead helps support the dimensionality and roundness of the head. This is an instance when it helps to “look around” the subject a bit if you don’t see that little bit of cap wrapping around and add it to your drawing.