Stubble pretty much nailed the beginner tips here. To expand on some points; Stand in front of the mirror with your shotgun and shoulder it so that your dominant eye is looking straight down the barrel. Practice this until that's just naturally where the gun goes, then while shooting keep both eyes open, point the shotgun rather than aiming it.
I wouldn't worry about gear. I shot my first month of sporting clays with a maverick 88 and my personal best was 39/50. I got my O/U and couldn't wait to break 40, I shot 39 again. It is very much the shooter more than the gun. You need to shoot and learn what you like/need before you start to compensate for shortcomings with gear.
The one concern with gear that really is important, is gun fit. By fit, I refer to not only LOP, but drop at comb, and cast. Unfortunately, most shooters have no clue as how to determine if a shotgun fits them, and as a result, many people are using shotguns that don't fit them. While it isn't foolproof, one way to get an idea of gun fit, is to close your eyes, shoulder the gun, and without moving any other body part, open your eyes. Are you looking along the rib, or down at the rib? Is the rib centered left to right? If you see a lot of rib, and a gap between the beads if there is a mid bead, there isn't enough drop at comb, and you will shoot high, if you see no rib, and only the top of the bead or no bead, there is too much drop at comb, and you will shoot low. If the rib isn't centered left to right, you will ahoot to one side of the target. Browning shotguns tend to have a lot of drop at comb, and Beretta shotguns much less drop at comb.
I operate a skeet field, so I see many beginners and experienced shooters, and a vast variety of shotguns. Many beginners share the same bad habits, and many shooters shoot shotguns that don't fit them. Some people have natural ability, and learn wingshooting very quickly, some have almost zero natural ability, and never improve, but most are somewhere in between, and do improve at various rates.
