Billionaires Bill Gates and Warren Buffett have been close friends for over 25 years. Whenever they get together, Gates admits, "I feel like a kid in a candy store." 

You get the picture, they're pals. And Gates is quick to acknowledge that Warren Buffett's wisdom has made a huge difference in his life.

One of the things Gates has openly admitted learning from Buffett is to value and protect the precious commodity of timeGates writes:

"No matter how much money you have, you can't buy more time. There are only 24 hours in everyone's day. Warren has a keen sense of this. He doesn't let his calendar get filled up with useless meetings."

Useless meetings are certainly one obstacle in the path of conquering your day and making you most productive. And successful people are keenly aware of centering their whole day around the things that matter the most.

Here's how they brilliantly manage their time, which is really another way of saying, how they manage themselves

1. They follow a predictable planning routine.

When you come into the office, your first priority of the day should be to avoid jumping into email. Because once you open your inbox, game over. You'll be sucked into a whirlpool of others' needs and having to put out fires.

Instead, map out the first 30 to 60 minutes of your morning to a planning ritual that you can follow daily. Ask yourself, "What do I need to do to start the day well," and "How much time should I allocate to each task?" 

2. They avoid open-plan offices to get real work done (and so should you).

The debate has raged on over the years: Do open-plan workspaces really help people become happier and more productive? 

I asked a behavioral science expert, Dr. Anja Jamrozik, director of research at Breather, to give us the bottom line. She told me, "The two tasks people spend the most time at work doing are: focused work and small meetings. Focused work is best done in a quiet space, while small meetings often call for private, collaboration-friendly spaces."

She says that open offices "are full of distractions that hinder both of these types of work," and that "any intelligible conversation is equally disruptive to cognitive performance," even if overhearing two people whispering to each other.  

According to recent research, says Jamrozik, overhearing half of a conversation, such as one side of a phone conversation, is even worse than overhearing a live conversation between two people.

3. They set a deadline for leaving work and plan their day backward.

If you want to leave the office by, say, 5:30 p.m., set that as your deadline and work backward. But first, make sure you schedule tasks you can get control and actually get done without interruptions. Point being, you want to rule the day rather than letting it rule you.

This is a strategy recommended by Cal Newport, professor of computer science at Georgetown University, and author of Deep Work: Rules for Focused Success in a Distracted World

Newton explains the strategy for mastering your day further: "Fix your ideal schedule, then work backward to make everything fit--ruthlessly culling obligations, turning people down, becoming hard to reach, and shedding marginally useful tasks along the way."

He concludes, "My experience in trying to make that fixed schedule a reality forces any number of really smart and useful in-the-moment productivity decisions."