2 screws: Do half or full turn on one screw, move to the next one and do the same thing. Repeat until they STOP, and don't force it further.
4 screws: Do half or full turn on one screw, move diagonally over to the next one and turn it, then move across to the next one, turn and move diagonally.
Repeat, diagonally, across, diagonally, across... until the screw STOPS.