Blurring Into Focus
Blond girl with gangly arms and a long slinder legs kicks this vampires butt and then...
But no, you have to sprinkle in the description without the reader noticing you did. If you wait too long to give the reader a description bone, they'll create their own image and snarl at yours when you try to slip it in.
The process should unfold slowly, like blurring into focus. At first you know the basics, it's a girl. As you ease on, an age attaches to her, next hair color and few more description sprinkles then viola...you have yourself one hot cupcake.