I don't post much but I have to say that you really need to get a better lens such as a Tamron or Sigma 17-50 2.8. The nifty fifty is also a good idea, try to shoot at a signle focal length for a while to better visualize what happens at each focal length and each aperture (lens opening). Get a better understanding of the effect of depth of field and shutter speed.
This was shot with a 5D on a tripod with a 24-70.