First draw a circle and a line up to the top of the head to the bottom of the chin
If u want bangs put a circle on the top if not u don't have to do that
For bangs u need to do this first-
Then draw lines curved and thin but they don't have to be all thin
Do the same thing for the side but less hair
On the top u want to make it look like the hair is moving and I'd u have gaps on on the side parts of the hair put thick and extra hair
For short hair all u need to do is the exact same thing but on the bottom
For longer hair u only need to do a little bit but if u don't like gaps u can do more
And that's all :P