Before I write another word, let me say that the photos that I have previously presented of both Emili and Jordon are no better than the two that I now present. To me, it is a matter of personal preference as to which one of the photos of them you prefer.
I present these adjusted photos (as requested in several comments) to merely show how a low-key version of Emili’s and a high-key version of Jordon’s photo might look. I do not think that you can get the same effect using Lightroom or Photoshop that you can be actually shooting with a given look in mind, but I do think that these are a relatively good representation of what the shots might look like.
It is totally up to you to decide which photo you prefer.
Lightroom 4—adjusted exposure and contrast to make changes to the respective photos.