Mistake: Staying in your child's room until he falls asleep

Your child will become dependent on you to nod off. And when he awakens in the middle of the night (as everyone does), he won't be able to fall back to sleep on his own. Not only will you not get enough sleep, but it'll also be fragmented, and not very restorative.

A better approach: Pave the way for your child to sleep in his own room by himself. "Stick to a specific bedtime," says Dr. Kushida. "Tell him that if he needs to use the bathroom or get a drink of water, he should do it beforehand. Follow a soothing routine  -- perhaps a bath and reading together  -- then say good night and leave."

Naturally, your child isn't going to like this at first. When my son, Liam, was a toddler, we got into the habit of playing a tape of kids' songs to lull him to sleep. The problem? If he woke up during the night, the music wouldn't be on, and he'd yell "Tape!" in a blood-curdling scream. My husband or I would run to play the tape, bleary-eyed from the interrupted sleep.

So we decided to cut him off cold turkey, which involved two horrible nights of Liam crying himself to sleep. We felt like the worst parents in the world. By the third night, though, he grumbled a little and started to snooze in about five minutes. So stay firm. Your child will eventually adapt to your new routine and everyone will catch more zzz's.

Mistake: Sleeping late on the weekends when your husband can watch the kids

Of course it's tempting, and you deserve the break. But sleep regularity is just as important as sleep quantity, says Amy Wolfson, Ph.D., author of The Woman's Book of Sleep. "If you've been sleep-deprived all week, getting a little extra on the weekends may be beneficial. But don't overdo it, or you'll throw off your sleep/wake cycle and Monday morning will be brutal."

A better approach: By all means, take your husband up on the offer. Just don't sleep in longer than one hour, which is enough to make you feel refreshed. Consider doing something else with the extra time  -- take a walk with a friend or read the Sunday paper uninterrupted.

Mistake: Not exercising at all or exercising too close to bedtime

Physical activity can help you nod off more easily and improve the quality of your sleep. How? No one knows for sure, but there are theories: It may help regulate your body's circadian rhythms. Or, because exercise raises body temperature during the day, your body may try to lower its temperature at night, which makes you drowsy. Or perhaps exercise cuts down on anxiety and other problems that may interfere with sleep. Exercising close to your bedtime, though, can make you too wired and your body too warm to sleep.

A better approach: Be active during the day if possible, but not within two to three hours of bedtime. In a recent study, women who worked out first thing in the morning reaped the most sleep benefits. If you take your child to preschool every day and you don't have to rush to work, wear workout clothes and exercise right after. Aim for 30 to 60 minutes per day of aerobic activity. Even a brisk 10-minute walk three times a day helps.

To fit exercise into her busy day, Lynn Lombard of Akron, New York, turned her basement  -- where she keeps exercise equipment  -- into a playroom for her 4-year-old. "That's the only place in the house where Amanda's allowed to paint or use play dough, so she loves being down there, and I get to work out in peace." She also started planning dinners in advance, so she has more time to work out.