A goldfish jumping out of the bowl(Photo: Courtesy of Women's Health)

1) Motivation Mistake: Setting the Bar Too Low

"I'll do my best" sounds like a worthy vow to make, but it can actually suck the motivation right out of you. "This type of vow is vague, making you more likely to procrastinate," says Gary Latham, Ph.D., a professor of organizational effectiveness at the University of Toronto's Rotman School of Management. The result? A mediocre or disappointing performance.

Solution: To step up your game, set clear, attainable, challenging goals, and give yourself a deadline. "Specific goals help focus your attention and increase your effort, which helps you persist longer," says Latham. And since you have a plan of action and a time frame, you're less apt to put things off. Another important point: Concentrate on three to five big goals at a time. "Any more and your eyes glaze over and you burn out," says Latham.

More from Women's Health:11 Personal Goals You Can Keep

2) Motivation Mistake: Testing Your Willpower

We spend three to four hours a day resisting the things we desire, says Roy F. Baumeister, Ph.D., coauthor of Willpower: Rediscovering the Greatest Human Strength. That's why you can turn down that frosted doughnut in the morning but have a harder time resisting the drive-through after work. Willpower can be exhausted from overuse, research shows, and when this happens, your brain either makes impulsive decisions or stalls out. "You shy away from complicated decision-making when your willpower is depleted," says Baumeister. "Rather than trying to perform the mental trade-offs to decide what's best, you look at one factor such as which item on the menu is cheaper, and base your choice on that." And, he adds, "the more often and the more recently you've resisted desires, the more depleted you are and the more likely you'll give in to the next one."

Solution: Try to take away some of those temptations- for example, reroute your drive home to bypass your favorite fast-food joint. Also, be sure to clock sufficient sleep and eat well and regularly. "When willpower is low, the brain craves glucose, but it's better to have something that will stabilize blood glucose over a period of time, such as lean protein," says Baumeister.

More from Women's Health:Science-Backed Strategies to Boost Your Willpower

3) Motivation Mistake: Aiming to Please Others

All that energy and determination you have when you first pinpoint a goal? It'll fade away if your motivation is sparked by the wrong things. For instance: "At the start of a weight-loss program, you're probably motivated by the desire to be slimmer, not to eat less and exercise more," says Kelly Webber, Ph.D., R.D., author of a study in the Journal of Nutrition Education and Behavior. And that kind of drive tends to be fueled by external reasons ("My class reunion is in two months!")-and is much less apt to end in success, according to this study. What works is autonomous motivation, when you want to do something for yourself. Webber found that women's motivation levels in the fourth week of a weight-loss plan predicted whether they'd drop pounds and last all 16 weeks of the program. At the four-week point, you know what it takes to be successful- and if you're still enthusiastic, chances are you'll keep at it.

Solution: To get yourself to that magic point, "find a friend, family member, or expert who can help you problem-solve when you struggle," says Webber.

See It, Be It?

Visualizing your success isn't the best motivator, according to new research in the Journal of Experimental Social Psychology. You may end up overlooking potential trip-ups and zap your chance to figure out ways to overcome or avoid them, say researchers at New York University. Plus, picturing yourself reaching your goal tricks you into feeling as if you're already there, so your brain starts to relax, your blood pressure falls, and you slide into complacency. Visualization of success isn't all bad, though; it can help you chill in stressful situations and determine which goals to tackle next.

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