Instructions
Start from an obvious point towards the back of the photograph, preferably with the person top left of the picture. This is because our eyes naturally read from top left to bottom right.
Make a note of where the identifying started. For example, "From top left, John Smith..."
Go around in as good a circle as possible trying to follow how a person's natural eye line will be drawn around the picture. Clockwise, going round in a circle from left to right as the hands of a clock move, is the best way for this, as people naturally expect a photograph to be captioned in this way.
Make additional notes as to the location of people, as there is a good chance the group is not going to form perfectly allowing for complete clockwise identification.
Add the location and date the picture was taken to complete the caption or description.