Let's see more ways or styles to do a face. We'll start with the eyes. We used similar eyes when we drew our kitten, remember? I use this eyes for human faces, cats, bears dogs... First, draw a four pixels line with black. Add two dots like here (I'm showing the images with 800% zoom):

Fill with a four pixels square:

Choose two degrees of the colour you want for your eyes. I'm using blue here, and paint like this:

Fill with three white pixels on each side of the eye. These eyes have a lot of bright!

Here you have some variations of colour:

Now, the mouth! Choose a light pink and paint something like this. (The horizontal lines are four pixels long):

Connect with a second horizontal line:

Add three dots (one in the middle and one on each side), and fill with a lighter pink:

Here is a zoomed image of a face using this style, and the dolls in their original size::

You can do your own variations, like I did here:

(There are the eyes of the girl in my "Back" button)