Sporting clays, hunting crows and shoot with both eyes open with a shotgun that properly fits you.
Often, the issue facing new waterfowlers, is the way they aquire the moving target. Many have never shot at targets that can move in a multitude of directions seemingly turning on a dime. So, they aim and fire, not accounting for speed, direction and angle of that duck or goose and often shoot behind or below it. Also occasionally, distance perception can play tricks on you. I always TRY to keep my shots within 40 yards (if hunting over decoys, measure the furthest one out to 35-40 yards as a distance indicator).
A technique that has worked very well for me is.... once your eye has aquired the target (duck etc) shoulder your shotgun while maintaining visual on the bird. Your brain is already figuring out speed and angle. Look down the top of your barrel (do not focus on your front sight) while staying focused on the bird. Follow the bird, squeeze trigger, continue to follow bird. You do not need to lift your head from your natural cheek weld to see if you have hit the bird or not. If you have missed, you are still tracking and are ready for a very quick second shot.
In order for this to become second nature you will need to practice shouldering your shotgun...a lot. So that it is the same everytime. Also, practice follow through. So when you are out shooting clays, continue to follow the clay if you miss or follow the original trajectory of the clay if you hit.
Crows are a pest and a lot of fun (and tricky) to hunt. Plus, in my neck of the woods they are ALWAYS in season so you can go out as often as time permits.
Lastly, I am also left eye dominant and right handed. Learn to shoot with both eyes open. I learned this years ago on a C7 and now apply it to all my guns and shooting styles. I will honestly say that my waterfowling accuracy improved once I started shooting with both eyes open (also, a bright fiber optic front sight doesn't hurt either).