(MONEY Magazine) – A friend once told me that his mother often said, "The more I have to do, the slower I go." Wise woman. But clearly she never worked in the new millennium. I, on the other hand, feel that I can't slow down some days: I have to get more done in less time. That's why I was happy to have six hours of airplane time recently—no phones, no e-mail—in the seat next to Julie Morgenstern, professional organizer extraordinaire and author of Making Work Work, a new book on becoming more effective at your job. Although she had work of her own to do, I grabbed her for advice on my problems: a never-ending to-do list and a feeling of unfinished business at the end of the day.

I was pleased to learn that my troubles are more universal than I expected. An awful lot of us are not as productive as we'd like to be at work—or in life. And ironically, tools like instant messaging, cell phones and that infernal wireless e-mail device—the "Crackberry," as some call it—aren't making the task any easier. For people with too much to do in too little time, Morgenstern suggests these four steps.

1. DO BIG STUFF FIRST Look at the tasks you have to accomplish each day and segregate them into big ones and small ones. Write a cover story: big. File expense report: small. The trouble is, most of us are inclined to knock off the small items first, figuring we'll get at least some feeling of accomplishment. But, says Morgenstern, it doesn't work that way. "Not only do you never get to the bottom of the stack of small items," she explains, "but working on them depletes your energy." The solution is to tackle the major jobs first. "Finishing one will give you more of a sense of accomplishment than finishing 14 little ones. Then you can use those endorphins to tackle the small stuff."

2. TURN OFF E-MAIL FOR THE FIRST 60 MINUTES I have to admit that I thought this was a joke. Wrong. Being swept up by e-mail as soon as you hit the office and pull the lid off your coffee is unnatural, says Morgenstern. "If your desk is constantly beeping, it never gives you time to concentrate or to complete a creative thought." Her solution is no e-mail for the first hour of the day. The longest your co-workers will have to wait to hear from you is 59 minutes. Then if during the day you need to give yourself time to concentrate, it's easier to turn a deaf ear to your e-mail chime. Why? You know you can because you did it once already.

3. STOP MULTITASKING During the '80s and '90s, we thought that the way to become more efficient was to do many things at once. Today, studies in publications like NeuroImage and the Journal of Experimental Psychology have found the opposite. If you stop working on a particular task and pick it up later, your brain needs 15 minutes to get back to where you left off. By stopping and starting, you're losing hours a day. How do you break the habit? Determine your concentration threshold, says Morgenstern: How long can you focus on one thing before you get "the itch"? It may be only 15 minutes. Stretch it by five minutes at a shot until you can work on a project for a solid hour or two.

4. LEAVE WORK 30 MINUTES EARLY Think about how you work on a typical day. Now think about how you work when you're on a deadline. You don't procrastinate. You're more effective. "Leaving work a half-hour early makes you work as if you're on a deadline all the time," Morgenstern explains. And what do you do with that extra half-hour? Something "restorative" that will let you go back to your routine refreshed the next day.

Works for me. I'm going for a run.