You us primarily one dither technique in this while Helm used many different types.
That hairline down her head shouldn't be so visible.
Here are some tips.
1. move the hair on the right side closer to the eye, it looks like its a wig thats slowly sliding off of his head :p
2. Looks very feminine. I would suggest adding ... um whats it called. You know when you dont shave enough the skin turns abit darker. Well helm has alot of that.
3. helms cheeks have alot more definition than in your picture.
4. maybe have alittle more color variation on the hair. and ad that tiny line of skin that shows through the hair right in the middle.
You captured the style of the spartan picture quite well. I would like to try that style sometime to.
Well the hair is sort of too far above the head. Look at some reference photos of random women to see what I mean.