Work on your composition. Can't Stress that enough.
Try learning with things other than a "model", and use your f1.4 lens until you really get the hang of composition and framing. Until you learn this, don't spend the money on a new lens, a Flash would be a very good investment. a Canon SB-600 would suit you very well...great flash.
Also, work on your focusing and Depth of field. And PLEASE fix your ISO, there is sooo much noise in nearly all of those pictures.
Good luck.