Trying to lose more than 10 lbs. in a month is not only unrealistic but also dangerous because it can throw your body’s electrolytes and metabolism out of whack. Instead, focus on dropping 1 lb. a week and sticking to a diet of 1,500 to 1,800 calories a day, says Katherine Tallmadge, a registered dietitian in Washington, D.C., and author of Diet Simple.

When exercising, keep your current fitness level in mind, advises Missy Beaver, a fitness trainer in Santa Monica, Calif. If you haven’t worked out in a while and go full steam ahead, you’re apt to injure yourself and then stop altogether. Start off by doing 20 minutes of cardio and 10 minutes of strength training, three days a week. When you find your routine getting too easy, increase the number of reps and up the cardio by 10 minutes. If you don’t see instant results, don’t quit, says Beaver. It can take three to four weeks to see visible body improve-ments, though you’ll feel stronger and more energetic in just a week.

Resolution 2

I’ll Enlist Support Troops

Dieters who get regular support from others are more successful than those who try to go it alone. Telling friends and family members about your goal increases your chance of meeting it, says University of Scranton psychology professor John C. Norcross, who has studied what makes people stick to resolutions.

“When you make your intentions public, it increases the attention to those intentions because others are watching you,” he explains. “There’s also the risk of embarrassment if you slip up and abandon your goal.” You can tell your spouse, a family member or a friend — anyone who makes a good cheerleader, says Norcross. See if there’s a neighbor who wants to swap low-cal recipes, or co-workers who’d be up for taking lunch-hour walks together.

Resolution 3

I’ll Mark the Mini-Victories

Rewarding yourself every time you lose 5 lbs. or overcome a fitness hurdle acknowledges your hard work and keeps you motivated. Make your reward something low-cost but meaningful, such as that fabulous new nail-polish color you’ve been eyeing, says Deborah Kern, Ph.D., executive director of lifestyle enrichment at the Lake Austin Spa Resort in Austin, Tex. Avoid prizes that sabotage your progress, such as a chowfest at your favorite restaurant.

Resolution 4

I’ll Mix It Up

When exercise feels like a chore, you’re more likely to bag it, says Beaver. So you want to avoid getting into a rut. To diversify a 30-minute cardio workout, try 10 minutes each on the treadmill, bicycle and elliptical machine, or skip the machines for a Pilates or kickboxing class. Just make sure you find your workout fresh and fun. “Try an activity that’s going to give you some pleasure, such as salsa dancing or yoga,” says Kern. One session with a personal trainer can also help keep you challenged and provide boredom-busting exercise ideas.

Resolution 5

I’ll Start a Breakfast Habit

Dieters often blow off breakfast, thinking the move will save them hundreds of calories. But forgoing that morning meal will only cause you to be hungrier at lunchtime, increasing the chances you’ll overeat.

And eating breakfast actually helps keep you lean: According to a recent study by the National Weight Control Registry of people who lost 30 lbs. or more, breakfast eaters were able to maintain their weight loss for a year or more. Start your morning with an energy-boosting meal packed with protein and complex carbs, such as cottage cheese and a slice of multigrain toast, or yogurt, fruit and 1/2 cup granola.