1. Believing Everything You Hear

During the first weeks with your newborn, you'll seek advice from everyone who's been there, done that. Even if you don't, they'll offer suggestions anyway. One acquaintance advocates sleeping with the baby. Your best friend warns against it. Your sister-in-law says it's okay to let the baby suck her thumb. Your pediatrician prefers a pacifier.

"The only opinion that matters is yours," says Alvin Rosenfeld, M.D., a child psychiatrist and author of Hyper-Parenting. "If you follow everyone else's advice, you give up the most creative role in your life."

2. Overestimating Your Free Time

Whether you're planning to take weeks, months, or years off from your job, don't kid yourself into thinking that being home with an infant is a holiday. Instead, you're starting a new job, with a tinier, more vocal boss who's so demanding that she won't even give you time off on the weekends.

Your plans to work out, catch up with old friends, and cook dinner every night just may not coincide with your baby's schedule.

3. Neglecting Your Spouse

After a long day of feeding, rocking, soothing, and diapering, you may feel like telling your just-home-from-work spouse to take a hike --a perfectly understandable reaction.

"There's nothing abnormal about having marital troubles and personal stress and feeling blue when your kids are little," says psychologist John Friel, Ph.D., a marriage counselor in St. Paul and coauthor of The 7 Worst Things (Good) Parents Do (Health Communications). "Making the transition from carefree twosome to parenting an infant is the biggest challenge to many marriages."

4. Putting Yourself Last

Making time for yourself after your baby is born is a necessity, not an indulgence, says Elizabeth Silk, a New York City psychotherapist who works with new mothers. Find time to talk to friends on the phone or go to a yoga class. "You need to nurture yourself so you don't become mechanical or joyless," Silk says. "The happier you are, the better parent you will be."

5. Not Sharing the Load

The learning curve is steep for new moms and dads alike -- so don't shut out your spouse. Let him find his way around the nursery. You may feel proprietary about the baby and you may initially diaper her faster or bathe her with more confidence. But your spouse needs to master these tasks too. Caring for a newborn is simply too much work for one person to do alone.

6. Assuming the Worst

Some babies have real health challenges or develop serious ailments that cause legitimate worries or concerns. But even a healthy child can exhibit all sorts of symptoms that trigger parental anxieties-blotchy skin, a cough, colic, diarrhea. Don't worry too much. "In today's society, we're trained to think we can control everything," says Martha MacCallum-Gregory, a Ridgewood, New Jersey, mother of two. "Accept the fact that you can't, and let go a little bit. Things are going to happen, and it's not because you didn't think to prevent them."

7. Comparing Your Baby with Others

Is she sleeping through the night? Smiling? Trying to sit up? Don't focus too much on developmental charts (they're averages), and don't let other parents make you feel as if your little darling is somehow slow because their child is already solving complex equations.

Babies develop at their own pace, and as long as yours is within the normal range, relax. A baby who crawls early isn't any more advanced than another; it just means more chasing for Mom and Dad.

8. Not Napping

According to psychologist James Maas, Ph.D., author of Power Sleep, new parents lose between 400 and 750 hours of sleep during their baby's first year.

You should snooze daily, if possible, or take at least one long nap on the weekend. Without adequate rest, it's hard to enjoy what should be a very happy time in your life. Sure, you'll have to sacrifice other things that could be done during naptime, but getting enough rest right now is more important than putting away the dishes.

9. Not Preserving the Moment

There are many ways to preserve your child's stages. Keep a journal, take photos, or videotape the simple everyday things -- you'll want to relive them for years to come.

10. Spending Too Much

"Everyone tells you the baby is going to change your life," says Alan Fields, coauthor of Baby Bargains and a father of two. "But no one tells you how parenthood will affect your pocketbook. You get sucked into Babyworld, and there is no escape." Like going to the grocery store when you're hungry, shopping can be risky for new parents. Fields estimates that a baby's first year will cost parentsat least $6,200 for diapers, clothes, food, strollers, and other essentials. His tip for avoiding overbuying: "Take an experienced parent with you when you shop, someone who knows what you really need and can cut through the hype." Go easy on clothes -- your baby will outgrow them in minutes.