Whenever drawing anyone/anything's head or face always start with a circle.

Hence, step 1 is to draw a circle ^_^

Next, know that human heads are not actually round, they're sort of oval/egg shaped.

So step2; make your head sorta egg shaped.

Next, whenever drawing something with any semblance of a face try and draw guides.

<= here I've cut the egg shape in half twice (once verticaly and once horizontally), be careful not to make the top half shorter than the bottom and try and make the two halves semetrical.

If there's one thing that's good to remember when drawing head on pics it's to keep things as symetrical as possible.