If it helps any more, I've found that (after hair) doing things like basic face shape, cheek position, and jaw/chin size help to get the overall shape and rough features in place to start with. Then I go through tweaking everything else, nose shape and size, eyes and eyebrow height, any changes to skin tone or face redness, etc. Changing the proportions of the lips and the position of the mouth, as well as the angle of the jaw (pointy or wide, etc) at the end helps to finish things off. It helps to work from a picture for comparison though and at the very least try and introduce some character into each one to make it less generic. The more options you play around with, the closer you should hopefully get, it just takes some time. That being said, I still don't know how some of the other guys here get their creations to be so realistic, but it's the same process, haha!
