with the seam of the jacket on the edge of the shoulder.
But every (casual with no shoulder pads) jacket I have that fits like that has a weird problem. When i move the arms the whole jacket moves too. If I put my arm up the whole side of the jacket goes up with it, so I constantly feel the jacket pulling when I move my arms.
When playing with it I noticed it stops doing this if you make sure the seam of the jacket is 1 inch away from the side of the shoulder (exactly on top of where your shoulder joint is), but it's hard to believe that every picture I can find of someone in a jacket is a bad fit.