Putting in the effort but still don’t have the abs you’re after? Here are 10 slipups that hold you back—and the right moves to get you on track.

  1. Your form is sloppy. “The wrong form can turn an effective move into one that won’t do anything for you,” says personal trainer Jessica Smith Gomez, co-star of the 10 Minute Solution: Best Belly Blasters. A few of the most common mistakes: pulling on your neck (which allows your abs to slack off), using momentum rather than muscle strength (again, a freebie pass for the abs), sagging your hips in plank, and not keeping your abs pulled in during every move. “You must control your abdominal wall to get any real benefit,” adds Erin O’Brien, creator of Kristi Yamaguchi: Power Workout and Strong Body Ageless Body. Check your form in a mirror to see how you’re doing. 
  2. You’re doing the wrong moves. “The worst exercise for a flat tummy is a sit-up, especially when done incorrectly,” says Samantha Clayton, personal trainer and co-star of YouTube’s BeFitin90 channel. “If you strain your neck, most of the work ends up being in the hip flexors rather than the abs.” The moves experts love: Pilates-based exercises, which work the deepest layers of the abdominals, plank poses, bicycle crunches, and functional movements that work the entire body (think kettlebells). Bosu and stability balls can boost the power of crunches, as these tools challenge your balance and force your core to work harder. MORE: 6 Surprising Moves For Flatter Abs
  3. You’re breathing incorrectly—or not at all. “Breathing should be a primary focus during ab work,” says Fred DeVito, co-creator of the Exhale: Core Fusion DVD series. Why? Your stomach sits behind the abdominal wall. Improper breathing pushes the stomach out, forcing the abdominal wall to protrude—the exact opposite of what you want during ab work. The correct way to breathe during a crunch is as follows: Inhale to prepare; begin to exhale as you pull your belly button toward your spine and start to curl up, keeping your abs pulled in throughout the move. “The challenge is to exhale as you pull the abs in,” says DeVito. “You’ll notice a difference immediately.”
  4. You’re eating the wrong foods. Photo by Stephanie Wißmann/Getty Images Experts agree: A healthy diet is the fastest way to flat abs. “You could do 1,000 ab exercises a day, but if you’re consuming too many calories, your rock-solid six-pack is going to be hiding under fat,” says Clayton. If you really want results, eat fewer refined carbohydrates (pretzels, bread, pasta) and watch your sugar and alcohol intake, as these foods tend to lead to belly fat. Instead, fill up on lean protein (such as beans, white meat chicken or turkey, lean beef, fish, and low-fat dairy) and non-starchy fruits and vegetables. MORE: The 6 Best Snacks To Eat Before A Run
  5. You’re stuck in a rut. “Doing the same exercises day after day without changing the number of reps or weight is a big mistake,” says fitness instructor Heather Schmidt. Personal trainer Suzanne Bowen agrees: “Your body is very efficient and it will get used to specific exercises very quickly.” No matter what your exercise of choice is—DVDs at home, gym equipment, studio classes—you should change your workout often. How do you now when it’s time to switch it up? “Once you’re no longer sore after a workout, you need to introduce something new,” says O’Brien.
  6. You’re mailing in your cardio. Swap your steady-state cardio workouts for interval training and you’ll burn through the extra belly fat faster. “All you have to do is up the speed of your movement—walking, running, swimming, cycling—or crank up the resistance for 60 or 90 seconds and then slow down or reduce resistance for another 60 to 90 seconds and repeat,” says Bowen. To keep your body challenged and avoid plateaus, regularly change the duration, speed, and resistance of your intervals.
  7. You’re focused on quantity, not quality. “There is no need to do 50, 100, or thousands of crunches each day,” says Nicole Nichols, creator of SparkPeople: 28-Day Boot Camp DVDs. Many people do more, thinking it will help them spot-reduce from the belly, but that’s a myth." The (very) good news: If you’re doing your abs exercises correctly, one to three sets of 8 to 20 repetitions per exercise is all you need to get results.
  8. You’re skimping on sleep. Photo by Tetra Images/Getty Images “Numerous studies have linked not getting enough sleep to weight gain,” says Smith Gomez. “Lack of sleep can affect your blood sugar, your hunger hormones, and even the rate at which you burn calories throughout the day.” One study published in the journal Sleep found that people who averaged 6 hours of sleep were 27% more likely to be overweight than those who slept for 7 to 9 hours. And those who only caught 5 hours of Zzzs were 73% more likely to be overweight. So turn out those lights and hop into bed a little early tonight—your abs will thank you.
  9. You’re speeding through your workout. Doing your reps quickly—instead of methodically—won’t give you a flat stomach. “Slow and controlled is best,” says Schmidt. “The slower one goes, the more muscle fibers can be recruited to complete the exercise,” making the move more effective. Another technique to try: “Instead of doing as many crunches as you can in 60 seconds, try holding one crunch for 60 seconds,” suggests DeVito.
  10. You’re a stress magnet. Chronic stress causes the body to increase production of the stress hormone cortisol, which can affect other hormones in your body, leading to weight gain, says Clayton. And those extra pounds are most likely to land on your belly. To counteract life’s nonstop stressors, do a few minutes of deep breathing exercises daily, meditate, or try to practice yoga regularly. (Try these 3 quick meditations anyone can do.) MORE: The Top 10 Workout Songs Of 2014