Combat training, Combat training, Combat training
Any time i make a change to my button setups, I go in combat training with the score limit set as high as possible and no time limit. Then I run around and try to obtain kills by only using whatever functions I changed (ex: Only running and knifing, only grenading, etc.). Of course it's also a great way to stop and adjust settings on-the-fly without the threat of horrible K/D's or hurting your team.
It may seem silly, but you'd be surprised how fast you can train your muscle memory to new button placements.
