the question if she paid was just a first question, not my comment
now that she is your sister, and didn't pay for these i will comment
as others have said she is not properly exposed.
1st, racoon eyes, you solved the problem without knowing you did in the second picture. position her head so light gets into her eye sockets.
this could be done many ways. and cheap you don't need a 400$ 580exII fill flash to get it working
1. Reflectors, great for blasting fill light into the eyes, 15$ of amazon, forum search or google search how to use them.
2. get her out of direct sun,
you can try this put her in the shadows of a tree or something so the light is more diffused and not hard light,
use a reflector with the black side facing her above her head, what this does is cuts the light off from going directly down, this forces light to only come in from in-front or the sides. again filling in the eyes
3. buy a flash. straight flash looks poopie so get an off camera flash with a umbrella, shoot through works great (expensive method)
on the second image, i feel your angle down on her is too extreme, makes it so she looks like a child looking up at the viewer.
the shooting down method is great, fills in the eyes, nice simple background (especially with a bokeh monster lens), and slimming effect, but you do not want to extreme of an angle otherwise it makes the subject seem inferior (right word slips my mind at the moment), kind of like she is looking up at the viewer, also she looks worried in the image.
Before going out and buying this lens that camera that flash do your self a favor.
and learn to see light, try putting your subject in shade, try using a $15 5-in-1 reflector to modify the light.
bets of luck to you