what your wanting is motion blur right? Like your taking a picture of a moving object, but you want the object in focus and the background a blur?
Your going to have to lower that 1/800 to something like 1/200, and "track" the object. You may have to go even lower then 1/200. Just try things out and keep going lower till you get it. It will take alot of practice, but as your holding the shutter don't hold the camera still. Move it WITH the object,
If your trying to get a blurred background on a still object, you need a lower Aperture. Basically, the closer you are to the object, and the further the object is away from the background behind it, the more blurry it will be! I hope this helps!