what i did in gow1 was hit and then hip fire

Hard to explain in text form, I advise you practice, practice, and more practice against bots on insane, and what not.

Well there is one way i used in Gears of War 1 that worked which was sprint towards enemy then fire, which would splatter there blood and guts on my screen or seriously injur that player at which point it is a one shot down with the shotgun. It works pretty well in gears 3 as well.

It depends on what you think youre better at with the shotgun. The two main ways i play (depending on map/ other team) is to out strafe the person you are 1 v 1 ing. Move left and right in unpredictable spurts while pop shotting or blindfiring. Or you could wall-bounce (pressing A to slide to cover but moving your left analogue stick backwards before you get stuck on the wall and firing your shotgun. Sorry if this sounds completely retarded but I find it hard to explain the tactics as it would be much easier to show you.

yah bro just a few hours a practice

then you will get it

im serious

dont go against bots on insane cuz all they will do is use the lancer, sniper, or hammerburst and aimbot your head the only good way is to practice against people on live and work on ur wall bounce as well to help you with positioning and try and try to quick scope with the shotgun. those are the best ways to work on your shotgun