The composition happens as the work progresses. Often the messy background makes it easy to disperse shapes as needed. I'd rather it took over me than I took over it.
People and things have edges, but where does a landscape stop?
I often use an old canvas and I particularly enjoy painting over something I've already done, allowing bits to come jumping through accidentally.
When I became tired of oil painting at one stage, I used collage and this proved to be influential in the design and composition of my later works.
And yet my life seemed to be just one big mass of people. I would never ask some people in for tea to fill up time. I just never would do it. Whenever I seemed to have a quiet hole, I would paint. That was what I would choose to do to fill up the time.