this is pixel art! this means that you will make it only by using a 1x1 brush.
before you start it is good to find the requirements you will be working under. i have decided to use four colors:
chapter one: creating the face structure
you begin by creating two lines that meets each other at a sharp chin. one of them should be smooth (the left one), and the other line should be divided into two sub lines where the first line goes straight down and the second line smoothly meets the chin.
after that you make two diagonal lines that goes from the two ends of your full line where they meet obisite to the chin. in the right of the picture you can then create a celshaded shadow starting thick and slowly fading out as it progresses. dot's of antialaising could be use in the right side of the picture.
chapter two: creating the hair
you start by making a line going from left bottom to right bottom covering the face, no need to perfect or anything. after that you create a line inside the the line you just created. you could maybe insert your face and then draw around it.
after you have done this you add color to your hair, even it out and add locks of hair.
after you have done this you add highlights to the hair. use a zigzag motion to create and effect.
then you can add shading to the hair.
after this you can define hair by adding one more color.
chapter three: creating the eyes
try making a Z. then make the below line smaller and the above line longer (thin in the end). add dots (as many as you like), and finish it off by shading it.
chapter three: putting everything together
now you need to place everything together. this is hard to do in paint so you could use TGF.
clean it and add shading to the top of the head that fits with the locks of hair.
give her eyes and eyebrowns and clean it out. and you are done: