Otherwise, secure the perimeter and stay away. Shut off the utilities only if safe. In looking at horizontal and vertical lines, start at the top of the building and work down. Look at doors and windows and compare the building to the one next door. When looking at paint lines, determine which building has moved.
Metal gates are easily pried open with a crow bar or tire iron.
Use two people. One person pries the door from the jam about BD inch, then the other person pulls the door open. Check the fire escapes in relationship to the windows. This is an indication of where the hallway is. Mail boxes and door bells give an indication of how many units are in the building.