Identify the covering
Felt, EPDM, GRP and asphalt are repaired differently. A product that sticks to one surface may be poor on another.
Look at where the water should leave
Persistent ponding can point to a blocked outlet, poor fall or sagging deck. The deepest puddle is useful evidence.
Keep a simple record: one wide photograph, one close view and the date of the weather event are usually more useful than a long description written from memory.
Edges deserve close attention
Upstands, corners, trims and pipe penetrations move and weather differently from the main area. A small opening at one edge can wet a surprisingly large section below.