Please, please, please, let them get higher than head height, taking into consideration if you are shooting up or down hill as well. If it isn't high enough, pass on the shot.
Our club had an ugly incident on opening day.
Lead that bird. Whether you shoot sustained lead or pass through doesn't matter, but, you will need a little more lead than with a modern cartridge shotgun.
If you pass on the shot, try to watch for where the bird goes down and mark it in your mind. You can often put them up again. Same with if you miss. If you have no retriever same thing will apply, mark where that bird went down, keep in mind that if only wounded, they will run when they land, if they don't just roost, of burrow under thick vegetation.
Have fun. Enjoy the sights and sounds.
Especially if hunting with a dog, Enjoy just watching that dog do what it loves to do. And, trust that dog's nose. Enjoy the experience.