What choke are you shooting? You really do want to start with the most open choke you have to widen your pattern.
Ok, I have a few things that helped me out, feel free to use them. I'll only address the ones you missed. It helped me out to start learning how to shoot the game with keeping the gun up, so I only had to focus on one thing at a time. On station #3, it helped me to start my gun farther away from the house rather than back all the way up to the house because I found myself playing catch-up the whole way across the field. Also, I usually try and start my gun on the same level as the bird comes out of the house. My advice for station 4 would be to try a little bit farther lead on the bird. On the right side of the field, it helped me when shooting doubles if I shot the high house where I would normally shoot that bird during the doubles. In other words, let the high house come across the field to you instead of shooting it before it crosses mid field.
"Sticks and Stones may break my bones, but political correctness is killing me."