RE: Recoil Management Training..
Okay, I just thought of one more tip. Use ear protection! Aspreviously mentioned flinching can be caused by things other than actual recoil like the loud bang when you pull the trigger. Using good ear protection at the range can minimize this. Not recoil management at all, but it can make you a more accurate shooter IMO.
As to the battle within I'm not sure how to help with that. I've always been one to state that "if you think you are cold then you ARE cold." The mind is a very powerful tool. Having a game or goal on your shooting can help when shooting paper a lot. Keep your mind focused on something other than the recoil.
Of course the largest caliber I've shot is a .338 win mag, and am happy with 2" groups at 100 yards so I'm not an expert by any means. I'm just sharing specific examples of things that have made me a better shooter.