Thanks to renji9, I now know this girl is Nagato Yuki :) I think she's on the cover of the Haruhi soundtrack.
I did this paper for Lonely Uta's challenge "Music is life". The picture of the girl came from here. I used two brush sets to make the background...one of which doesn't have an author brush, so I couldn't tell you who made the sparkly brushes. :( It's been too long ago now. The music ones, however, are by Jenn's Sanity, so kudos to her for such nice brushes.
Um, as for how I made this...well, um, I started by cutting the girl out of the other picture, obviously. Once I had her out, I opened a separate file and started making the background. I picked out a purple I liked and did the music brushes over it in white. Then I played with the contrast/lightness/darkness/color adjustments until I liked the way it looked. I think I added a weak purple light to it too to make it a bit darker. Um, then I put the girl on top of that and did the other brushes in various states of transparency until I liked the way it looked? I hope that explanation is good enough for the challenge >_< I kind of just play with pictures until I like the way they look. >_<
Hope you like it!