I enjoy working with oils but have fewer paintings in this medium since I need more time to dedicate to them.  I use a similar approach to these paintings as I do to my pastels, and the subjects are usually the same.  These paintings are done from my photos and sketches, since I seldom use oils for plein air painting.  When I take a picture of a scene that I want to use for a painting, I take my photo with composition in mind.  That helps me when I am ready to start my sketch on the canvas.