Don't fire at birds when too near.
Don't try long gallery shots. It is cruel.
Don't fire at your birds, but in front of them. The exceptions to this, are birds coming direct to you or going away.
Don't potter in your aim, but aim and fire quickly.
Don't, if you can help it, shut either eye.
Don't wound. If you can't kill neatly, don't fire.
Don't fire at a pheasant's tail feathers, but try to intercept his head.
Don't climb over stiles with a loaded gun.
Don't keep your cartridges in the gun, except when actually waiting for game.