Skeet shooting consists of crossing targets.  You can set this up with 2 machines.  1 clay in one direction, 1 clay from the other direction, then both clays at the same time.  Shooting in 5 positions 

National Skeet Shooting Association

Trap Shooting

Clays shoot out away from the shooter.  Shooter should be approx. 16 yards behind the trap, further for more experienced shooters.  Shooting in 5 positions. Add the auto wobbler, and random shots will be more challenging.

National Trap Shooting Association

Sporting

This most simulates field shooting.  Set up 5 different shooting stations depending on course layout.  Trees and water provide a natural shooting setting.  Trigger the first trap, and trigger the second trap at the sound of the first gunshot.  Add a real challenge with a rabbit trap in the mix that bounces across the ground as a bonus round.

National Sporting Clays Association

5 stations to shoot from.  It is best ot have 5+ traps to throw targets from.  Set up a wobbler or oscillating base on one trap for a more challenging course.  Set up one trap throwing back towards the shooting stations.