I might sound silly but I would suggest that you try drawing on paper before tackling this with pixels. Pixel art might be a completely different beast from pencil drawing, but if you feel so unsatisfied with your attempts that you posted a blank face, ask yourself if you feel comfortable with how you would draw it at a similar scale if you weren't limited to the pixel grid in the first place, and if you are not, then work on it. The way you render stuff with pixels will always be somehow tied to the way you capture the shape of things in your mind and the way you instinctively draw stuff on paper when not stressing about it. Perhaps you might find that what you would like to change isn't how you rendered with pixels but how you are imagining the lines, volumes etc.