As the other guys have said; hold it firmly on the shoulder and a custom fitted fitted recoil pad. A shotgun should be pointed, rather than aimed. So in other words, every time you pull it to your shoulder you are looking straight down the barrel - not a bit left or a bit right. I did a fair bit of skeet/claybird shooting and my recoil pad is offset so everytime I shoot at a claybird I just point the gun and pull the trigger. This would also be good for a self defence tatical situation too where you don't have time to aim. Shotguns are fun once they are sorted
and that 870 should be particuarly good.