With the object still selected, open Photoshop’s new Content-Aware Fill tool, which opens in a new window. You don’t have to be exact with the selection - in fact, it’s probably better if you get a small portion of the background in the selection instead of selecting along the exact edges. You can use any selection tool, but the lasso tool (the third tool in the lefthand toolbar) is often fastest for selecting odd shapes. (Alternately, you can also select a gap or hole that you want to fill). With the photo open inside Photoshop, select the object that you want to remove.
