Tim Grover, author of RELENTLESS: From Good to Great to Unstoppable is known for his training and mental preparation for the most elite athletes in the world.  He's trained Michael Jordan, Kobe Bryant, Derek Jeter, Dwyane Wade and many other elite, hall of fame athletes. He strongly believes in mastering one thing and making yourself invaluable.  Leverage your contacts but make sure you have something to back it up.