What should you be asking/looking for when choosing a photographer?
If they are going to be there all day. Make sure you ask to see proof of there work. See if they are friendly and approachable as you want them to mingle with guest to get great photos.
Find out how flexible they are. I found some of them had set packages and didn't want to deviate. When I met the photographer we booked I just knew she was the one as she was interested in us, what we wanted and had lovely work to show us. It is very important they can relate to you as a couple or your photographs will not be what you want.