(FORTUNE Magazine) – ONE OF MY FAVORITE New Yorker cartoons of all time shows a harried-looking middle manager sitting at his desk. Every square inch of available flat surface around him, including the window, is covered with Post-it notes, and he's saying into the phone, "Okay, Bob, I've got you on a stickie." Maybe it cracks me up because, in trying to keep track of multiple projects, I plaster my desk with stickies too. Every once in a while, though, and usually during New Year's resolution season, I start thinking that there has to be a better way.

Enter time-management guru Stephanie Winston. Her latest book is Organized for Success: Top Executives and CEOs Reveal the Organizing Principles That Helped Them Reach the Top (Crown Business, $21.95). The subtitle is the key to Winston's approach. She spent several months snooping into how big kahunas manage to stay so serene--and keep their desks so tidy--while bombarded with ceaseless demands on their time and attention. Many of the practical, day-to-day methods Winston observed might be useful to ordinary mortals who would just like to leave the office before the cleaning person starts running the vacuum.

How, for instance, do you fend off constant interruptions during the workday? Kent Crawford, CEO of project-management consultants PM Solutions, found that incessant "got a minute?" drop-in visits were wrecking his concentration. He now has direct reports send an e-mail asking to speak with him at a particular time, so he can reply, for example, "3 P.M. isn't good. How about between noon and two?" Crawford says, "This way I'm highly accessible but still get to control my time." Other executives Winston interviewed update their voicemail greeting daily and include mention of that day's visiting hours, when the door will be open to anyone who wants a quick word.

Still, the author notes, the most successful senior managers are those who welcome constant contact: "To a CEO the torrent of questions, comments, updates, requests, and expectations--perhaps hundreds a day--is a rich resource to be mined." Intel co-founder and chairman Andy Grove says he leaves plenty of "air pockets" in his daily schedule to accommodate ad hoc meetings. So how do these hands-on bosses get any thinking done? Well, apparently it helps to be a morning person. Getting up very, very early to use dawn hours to grab some quiet time is "simply part of the territory," Winston writes.

The biggest mistake most people make, according to Winston, is multitasking. "Successful CEOs do not multitask," she told me. "They concentrate intensely on one thing at a time." What stops the rest of us from doing likewise is a reluctance to set boundaries, she says. "People tell me they feel guilty if they turn off their instant messaging, even though it drives them crazy," Winston says. "But how can you do your best work if you're constantly distracted? It's perfectly okay to say, 'No, I'm busy right now.'" I, for one, plan to try that in the New Year. In fact, so I don't forget, I'll put it on a stickie.