Position a ladder carefully against the side of the house and climb up onto the roof. Walk slowly around the roof, shining your flashlight on each square foot of the roof. Examine the drip edge, the vents, shingles and fascia for dimples or dents.
Angle your flashlight this way and that, turning it as you examine each square foot of the roof. Imitating the sun's angles in this way allows you to reveal hail damage that you ordinarily would not see. Pay close attention to shady areas, as the shade can often hide a lot of damage from hail.
Climb down from the roof and position your ladder beside the gutters. Run your flashlight up and down the length of the gutters, angling it this way and that way to reveal indentations and dings you might not have ordinarily seen.
Walk around the structure, shining your light onto each downspout. Look for shingle mineral deposits or dents around the downspouts. These are also signs of hail damage.