Regardless of your goals—to pay down credit card bills, get along with your mother-in-law, lose a few pounds—these three steps will help make your New Year’s resolutions a reality.

If you’re like nearly 50 percent of Americans, you made at least one New Year’s resolution on January 1, most likely involving your health, money, or improving a relationship. But research shows that many of us abandon our resolutions by mid-February. How can you avoid being part of that daunting statistic? John C. Norcross, PhD, a distinguished professor of psychology and coauthor of Changing for Good (William Morrow, 2007), knows how. His research shows lasting change happens in three stages.

STAGE 1: PREP TIME

Start by taking a few minutes to clearly define a realistic and measurable goal. Rather than trying to get to what you weighed in high school, set a modest goal of losing just 10 percent of your body weight in six months. For example, you could create a 500-calorie-a-day deficit by logging 250 calories worth of steps on your pedometer and cutting 250 calories from your diet by, for instance, switching to skim milk and nixing your midday frappucino. If you think this seems precise, you’re right. To be successful, your goal has to be specific, Norcross says.

Next, plan a healthier substitute for any behaviors you’re trying to eliminate, for example, tea with lemon instead of that frappucino.

While you’re in the prep stage, troubleshoot. Before vowing to take a brisk walk every morning, ask yourself why you haven’t done that before. Will it disrupt your schedule? Are you really not a morning person? If your resolutions aren’t a good fit for your schedule, lifestyle, or your personality, tweak them until they are.

STAGE 2: TAKE ACTION

Once you have a measurable, realistic, and doable goal, and a healthy surrogate for any habit you’re trying to give up, you’re ready to just do it, right? Not exactly. Check the timing. If you’re changing jobs, moving, or otherwise going through any other major life transition, put off implementing your New Year’s resolution until the dust settles.

When your life is relatively calm, you’re ready to plunge in and actually make the resolutions you’ve been planning. Go for it—but be sure to reward yourself frequently so you’ll keep up the good behavior. And while you’re at it, try to control your environment so old behaviors don’t tempt you. If weight loss is your goal, spend time with active people and avoid high-fat restaurants.

During the action stage, which typically lasts two to six months, you’ll also need to implement that long-term healthy substitute you planned for, such as taking swigs from your water bottle instead of opting for a caffeine/sugar fix. You’ll also want to avoid a saint-or-sinner mentality. That is, when you lapse into old behaviors (don’t kid yourself, you will), don’t fall prey into thinking, “Well, I overate, I might as well give up.” That’s demoralizing and demotivating. Instead, simply get right back to your new routine.

Stage 3: MAINTENANCE

At this end-of-the-line stage of behavior change, your New Year’s resolutions are reality. To avoid reverting back to your old ways, you’ll need to continue everything you were doing in the action stage: rewards, environmental control, opting for a healthy substitute, and snapping back after a slip.

That is, unless you’re among the select few who reach the final, be-all, end-all stage of behavior change: termination. At this utopian juncture, your former, less-than-healthy habits feel as foreign to you as your new habits once did. Congratulations: You’ve developed a new lifestyle.

Sandra Gordon is an award-winning freelance writer who delivers expert advice and the latest developments in health, nutrition, parenting, and consumer issues.