i dunno.
but here's my $.02....
dont' shoot at out of range birds.
don't shoot at birds that will fall in an area you can't find/retrieve them.
make every effort to retrieve them.
treat the game with respect.
don't set up close to another party.
don't call at birds another party is working.
if you can't blow a call, don't call.
learn how to shoot your gun accurately, and stay withing your skill limits.
use the proper shell and choke for the conditions.
pick up your trash.
encourage other people to try this sport.
don't shoot the hens.
don't go into the marsh 30 minutes before legal shooting time and try to set up. other people have already done this several hours earlier.
keep your dog under control.
keep your cell phone on silent/vibrate mode.
give back to the resources.
that's all i can think of for now, but there is more.