Theres lots of head tutorials out there, some simple some complex, Dave K's poly head tutorials pretty good, a bit messy to start out with but pretty cool results if you stick at it.

https://www.highend3d.com/maya/tutori...lygon/303.html

As I said theres lots of them with different methods for each so your probably best off looking for some then discussing between youselves which ones in your skill range and has the results your after.