Different influences at different times in my career, and some have stayed with me more, some less. Chester Himes. Ralph Dennis, who wrote a series called Hardman which is a big influence on the Hap and Leonard novels. Harlan Ellison, Philip Jose Farmer, Gerald Kersh, Fredrick Brown, Robert Bloch, and I'm just getting started. I read constantly. As for the epic Western, that's Paradise Sky.
Think about the photo before and after, never during. The secret is to take your time. You mustn't go too fast. The subject must forget about you. Then, however, you must be very quick.