Ballet Dancer (Grey Pencil) Unfinished

I started this drawing on Christmas Eve 2015 and I haven't touched it since.

I used as a model an hyperrealistic oil painting of a ballet dancer made by  Sergio Martinez Cifuentes (Chilean-Spanish painter) called: "Quiebre en malvas"

 Here is a link to his webpage: http://www.sergiomartinez.com/inicio.php