"Interaction should be constant, not crammed into meetings once a week. You just turn around in your chair and bounce an idea off one of the other 10 people in your office. Keep the floor plan open so people can talk to each other. As the company gets bigger, keep dividing it into smaller and smaller groups. Follow Jeff Bezos’s two-pizza rule: Project teams should be small enough to feed with two pizzas. At Hunch, we don't have meetings unless absolutely necessary. When I used to have meetings, though, this is how I would do it: There would be an agenda distributed before the meeting. Everybody would stand. At the beginning of the meeting, everyone would drink 16 ounces of water. We would discuss everything on the agenda, make all the decisions that needed to be made, and the meeting would be over when the first person had to go to the bathroom."

Caterina Fake is the co-founder of the photo-sharing site Flickr. Her new start-up is Hunch, a website in New York City that takes user input to make recommendations on thousands of subjects.

"Communication is key. I call the CEO or chairperson of every one of my major clients every day. I like the directness of phone conversations; you don’t miss things the way you do with e-mail. I also carry my cell phone around the building, and my employees do as well. We have a rule: I answer their calls and they answer my calls. Also, cut down on sleep. Why would you sleep when it’s time to live? Sleeping isn’t living. You sleep when you die. I get up at 3:30 every morning and I’m at the gym by 4. Then I ride 25 miles on my bike before breakfast. Being in shape is what gives me energy."

Jordan Zimmerman is the founder of Zimmerman Advertising, which has 22 offices and billings in excess of $2.6 billion.

"My executive assistant, Haley Carroll, e-mails me a daily memo, which I read after I go home every night. It's in four parts, and the first part is my next day's schedule. Then comes a list of questions that cropped up during the day -- maybe someone wants to know whether I have feedback on the new Hudson Yards Catering logo. She aggregates them so she doesn't have to interrupt me repeatedly during office hours. I'll respond to those right away. The third part of the e-mail is FYIs: information I don't have to act on but might like to know. Maybe my mother called to make a reservation for her neighbor next week at Blue Smoke. Or there might be a change in my schedule. Finally, there is a section of longer-term reminders. I promised to write a blurb for a friend's book. I want to plan a vacation, so I need to check on my kids' school schedules. We started the memos only last year, and I don't know how we managed without them. I care about the details. This way, I don't worry that I'm missing anything."

Danny Meyer is the CEO of Union Square Hospitality Group, which owns 13 New York city restaurants, including Gramercy Tavern and Eleven Madison Park.

"I used to think business was 50 percent having the right people. Now I think it’s 80 percent. The best way to be productive is to have a great team. So I spend more time than most CEOs on human resources. I carry a little notebook with the names of 35 or 40 people in the company, and every week I look at it to make sure I’m in touch with everyone. The top eight or 10 people I’m going to see automatically. But there are always 20 or 30 people who are up-and-comers or one or two levels down, and I wan them to know I’m paying attention. Once a quarter, I go through my list of contacts—a couple of thousand of them—to see if there’s anyone I should be reaching out to about a job. Intensive as all of this is, I ultimately save time, because I can delegate with confidence."

Kevin P. Ryan’s encore to DoubleClick—the ad-serving behemoth he sold for $1.1 billion to private equity firm Hellman&Friedman in 2005—is AlleyCorp, a variety pack of Internet start-ups he founded in New York City.

"Zipcar challenged us to think about how we could use a car on an hourly basis instead of a daily basis. I’d like to challenge business people to think about what they would do if they could have talent on demand. Hiring contractors is more cost-efficient than hiring people full-time and less time-consuming than doing it yourself because you can hire an expert for whatever task you need to accomplish."

Julie Ruvolo is co-founder and COO of Solvate, a New York City-based provider of offsite office assistants.

"Make the next day’s “to do” list before you leave the office. Rate each item A, B, or C based on its importance, and work on A items first. The productiveness of any meeting depends on the advance thought given the agenda, and you should never leave a meeting without writing a follow-up list with each item assigned to one person. And go outside. All the big ideas are on the outside. You’ll never have a creative idea at your desk."

Barbara Corcoran made her mark building one of New York’s largest real estate companies. Today, she is a panelist on the ABC program Shark Tank and runs a much smaller firm that works with the start-ups she chooses to invest in on that show.

"When scheduling travel and social activities, I like to communicate plans through e-mail to both family and colleagues to keep an easy record of correspondence rather than relying on a possibly hurried conversation."

Karl Hoagland is the founder of Larkspur Hotels and Restaurants, in Larkspur, California. It recorded $20 million in sales in 2009.

"A lot of productivity is capturing ideas. I use a wiki—it’s more valuable than e-mail for running a company—and I have a page for every person with whom I interact frequently."

Garrett Camp is the founder of StumbleUpon, a Web service in San Francisco that helps users find relevant content based on others’ recommendations.

"I get almost as much done outside normal office hours as during them. I’ll interview people on Saturdays, late at night, early in the morning. If I’m trying to solve a particularly difficult problem, I’ll come in on the weekend, when there’s less going on, and spend a day focusing on it. I read technology manuals and watch video tutorials late at night. During start-up, I think you have the choice of being productive or having a social life, and I’ve choosen being productive."

Seth Priebatsch (center) is CEO of SCVNGR, a Boston-based start-up that helps organizations engage people through location-based smartphone games.

"If I think something is going to take me an hour, I give myself 40 minutes. By shrinking your mental deadlines, you work faster and with greater focus. I also schedule time every week on my calendar for quiet, concentrated PowerTime where I only work on my most important activities. A “Stop Doing” list is as important as a “To Do” list. A “To Do” list is easy, you just keep adding to it and the more you have on it, the more important you may feel. But “Stop Doing” is more difficult because you have to give up some things."

Krissi Barr is the founder of Barr Corporate Success, a business consulting firm in Cincinnati. She is also the author of Plugged – How To Dig Out and Get The Right Things Done.

"With the exception of one or two days a year, I work out every single day. Fitting a workout into the work day reduces stress, keeps you healthy, and is great for getting “alone time” to work out business and personal problems. When someone asks for a non work-related meeting, see if they are up for doing the meeting while running or biking together. Work out at lunchtime and then eat at your desk."

Mike Cassidy is the CEO of travel and tour site Ruba. He has also been the co-founder and CEO of Xfire (a company that helps gamers play online with their friends), Direct Hit (an internet search engine), and Sylus Innovation (which produced a computer telephony software).

"For me, a big part of productivity is being agile. I like to leave a lot of blocks in my day open. On an average day, I'm only 50 percent scheduled, though occasionally it gets as high as 80 percent. That's imperative, because often something comes up out of nowhere. Recently, for example, an important new partner came to the office and unexpectedly brought the CEO. The team came to me and said, "Oh, my God; their CEO came. Do you have a window this afternoon?" I had a window. And at the end of the hour the CEO and I spent together, we'd identified new markets and positioned the company to be a global as well as domestic partner. If I have a free block and nothing presents itself, I catch up on industry reports, self-education, and big-picture thinking. In a packed schedule, those things can get neglected. They shouldn't be."

Scott Lang is CEO of Silver Spring Networks, a developer of smart energy grids, based in Redwood City, California.

"Don't multitask. Multitasking is something we all do these days. The problem is our brains just aren’t cut out for it. When you multitask, you’re interfering with your brain’s ability to perform at max-capacity. Yes, you can walk and chew gum at the same time. You can fold laundry while talking to a friend on the phone. Clowns can ride a unicycle while juggling brightly colored balls. These are role tasks that don’t demand a lot of brain power. But in most cases, multitasking=lesstasking. When you make those shifts from one context to another, you risk dropping things from your short-term memory. Do one thing at a time, minimize context shifts, maximize brain power!"

Douglas Merrill is the author of “Getting Organized in the Google Era” and former CIO of Google.

"The most difficult aspect of being a CEO is you driving your day, and not letting the day drive you. By looking through tasks each morning and resolving to allocate the time to concentrate on the CEO priorities, the actions only the CEO can take to move the company forward, you can keep your eye on moving the company forward. At the end of the day, I always checked whether I had taken action on my top three priorities. If the answer was "no," I stayed in the office until I made progress on them."

Bob Compton is the CEO of Vontoo, a voice broadcasting technology company, and the Chairman of ExactTarget, an on-demand e-mail marketing and one-to-one digital communication platform.