If you are using an 870 it probably has a field stock. I use an 1100 with an adjustable comb to raise the stock which will raise the angle of the gun.
This makes the gun shoot higher. In the case of a field gun it will usually shoot low. You will probably need to cover the clay with the barrel to hit it.
Its a game of pointing not aiming. You need to know where your gun is shooting. Also hold both feet about shoulder width apart at an angle to the house. For a while i used a stance kind of like one in martial arts with one foot forward. That really hurt my swing and made it un even. Watch the other shooters preferably the good ones to find the way they stand. Then mimick them. Afterwards go home and practice the foot stance and swing your gun till you feel comfortable. It may take a while but it should feel like a smooth natural movement.
Last tip keep your cheek on the stock and assuming your right handed your right elbow high...You arent shooting a rifle here. And always move your body not your arms. Once you move your arms and not body you actually change your hold and you miss.
A friend told me and sorry not to be gross but shooting trap is like jerking off.
You can hit the ceiling or the floor. You dont aim to do either you just do it.
Take care and
Practice a lot on and off the line....Shooting that is.
Before you know it you will be scoring 22's and gettting pissed you cant do 25 then it becomes something like golf.
Serious IT IS SO MUCH FUN!!!!! I LOVE TRAP
This makes the gun shoot higher. In the case of a field gun it will usually shoot low. You will probably need to cover the clay with the barrel to hit it.
Its a game of pointing not aiming. You need to know where your gun is shooting. Also hold both feet about shoulder width apart at an angle to the house. For a while i used a stance kind of like one in martial arts with one foot forward. That really hurt my swing and made it un even. Watch the other shooters preferably the good ones to find the way they stand. Then mimick them. Afterwards go home and practice the foot stance and swing your gun till you feel comfortable. It may take a while but it should feel like a smooth natural movement.
Last tip keep your cheek on the stock and assuming your right handed your right elbow high...You arent shooting a rifle here. And always move your body not your arms. Once you move your arms and not body you actually change your hold and you miss.
A friend told me and sorry not to be gross but shooting trap is like jerking off.
You can hit the ceiling or the floor. You dont aim to do either you just do it.
Take care and
Practice a lot on and off the line....Shooting that is.
Before you know it you will be scoring 22's and gettting pissed you cant do 25 then it becomes something like golf.
Serious IT IS SO MUCH FUN!!!!! I LOVE TRAP
Go to some of the better shooters and ask them how they do such a great job. 
