This year, you've vowed to lose weight, shape up, and cut back on caffeine. Or perhaps you're determined to quit smoking for good. Maybe you've decided it's time to get to bed early, no matter what. If any of this sounds familiar, you're not alone—more than 100 million Americans make New Year's resolutions every year, according to researchers at the University of Washington.

The bad news: Nearly 60 percent of those same well-intentioned Americans abandon their pledges by the six-month mark. Why the high drop-out rate? Most people don't properly prepare to see their pledges through. Want to defy the odds and achieve lasting change? Follow these tips to make resolutions that stick.

  • Keep it real.
  • If you've been a couch potato for years, it's unlikely you'll morph into a bodybuilder after the ball drops. Instead, set your sights more realistically—on, say, hitting the gym three times a week and logging 10,000 steps a day on your pedometer.

  • Put yourself on notice.
  • According to experts, you shouldn't wait until the stroke of midnight on New Year's Eve to declare your resolutions. Instead, make them at least a week in advance so you'll have time to prepare.

  • Make a plan.
  • Simply announcing that you're going to quit smoking during "Auld Lang Syne" isn't enough. To break the habit, you'll need a plan that includes, for example, talking to your doctor about smoking-cessation aids and removing all the ashtrays from your home.

  • Break it down.
  • When resolutions seem overwhelming, they can be harder to keep. So, instead of simply vowing to shed 30 pounds, break it down into more manageable mini-goals of five pounds a month.

  • Seek out support.
  • Once you've settled on your resolutions, tell everyone what you intend to achieve. When friends, family, and coworkers are aware that you're trying to eat more healthfully, they'll be much less likely to stop by for lunch with a Big Mac and large fries.

  • Create reminders.
  • When you wake up feeling groggy on New Year's Day, you'll know exactly why you need to get more sleep this year. Come February, though, you might not remember. To remind yourself, create a journal describing how much better you feel when you go to bed early.

  • Reward yourself.
  • If you've managed to swear off cigarettes for a month, you may not be completely out of the woods yet, but there's certainly cause to celebrate. Acknowledge your success with healthy rewards, like a day at the spa, a new iPod, or a cool pair of sneakers.

  • Visualize it.
  • If you're determined to shape up, remember that it's not only a matter of sweating and crunching the numbers. It's important to picture yourself as a fitter, sleeker, stronger person. Mental imagery can be a powerful motivator, reminding you that your goals are well within reach.