Watching Spieth play some of his best golf at the President's Cup offers a glimpse into the unique relationship between Spieth and his caddie, Michael Greller. Greller's critical task (probably dozens of times per day): influence without authority. In business, one of the biggest surprises for executives in their first C-suite role is just how important this skill set becomes. "Garnering buy-in," "getting alignment," and "cross-functional collaboration" are no longer buzz words and nice-to-haves but imperative for driving strategy and execution on a senior leadership team. Many leaders struggle to make this leap. Maybe Greller has a few lessons.

1. Know your stuff.
2. Educate rather than sell. 
3. Depersonalize. 
4. Stop talking.   

Knowing your stuff is about doing your homework and being an expert at your craft. Having confidence in your knowledge base means you will add real value to every initiative, and you will be less likely to succumb to proving, bulldozing, and the like. 

Educating is about dispassionately sharing the most relevant information. Not using data as a weapon (or a shield), but instead sharing your most valuable knowledge freely and without expectation. 

Depersonalizing means recognizing and accepting that sometimes people will not understand, believe, or follow your (very sound and very right) advice. They just won't. It's not a referendum on you; it's not about you at all.  

And the best, highlighted in this fascinating snippet from this summer -- know when to stop talking. It's surprising how often subtler versions of "I told you so" or "that was my idea" sneak into senior team dynamics. If the results tell the story, let them. Extra commentary is just noise.