I've done a fair amount of aerial photography flying in a 172 recently.
As far as the aircraft configuration is concerned, we take the latch/strut off the window. As long as the photographer is careful they can open it up in flight and it stays open parallel to the wing. Photos are quite easily taken by keeping the camera pointed just ahead of or behind the wing strut. The photographers I fly with have never mentioned having a problem with the strut.
As for flying the aircraft, I normally extend 10 degrees of flap- enough to slow you down a bit, but not enough to get in the way of a picture.
Taking photos of subects on flat ground is relatively simple- fly straight and level. However when the subject is higher such as including a hill in a scenic shot or an air-to-air shot the wing itself can sometimes be in the way. I was always told not to, but in these cases I fly with slightly crossed controls- lift the wing with aileron and keep heading in the same direction with opposite rudder. Just don't let your speed get low!
That's how I do it, I'm sure other people will do it differently though
