Just to clarify, I'm not a Michael Phelps fan. I love the spectacle of the Olympics, but I think that swimmers benefit from all the different events they're able to compete in. Still, I have much respect for consistency, and I think that Phelps might be one of the most disciplined athletes of our time. I hold to my hypothesis, that it was ridiculous to try to get inside Phelps' head.
It was my friend, Aaron, who introduced me to locus of control. Another tidbit that's interesting to dive into is the correlation between religious people and locus of control (this article [not an endorsement] attempts to grapple with it).
I'd encourage you, if you're interested in eliminating some bad habits or creating some good ones, to get a copy of Charles Duhigg's book. It's a fascinating read that provides a systematic approach to getting better at this thing called life.
Links if you're interested:
Shadow boxing in front of Phelps
Power of Habit on Amazon