9 back-to-school mistakes parents make

Don't corner the teacher to share a variety of personal details about your child while he or she is standing right next to you, says Lietz. Children have ears too and often find this embarrassing. What's more, the first day of school is hectic and the teacher will need to greet other children and parents. If there is something important to share with the teacher, Lietz suggests putting it in writing and letting the teacher know that way.

When it comes to young children, make good-byes quick, says Lietz. It's OK to linger until they're comfortable, but don't watch them nervously and wring your hands. Children often pick up on their parents' anxiety and it makes them anxious as well. If your child is resistant, firmly state, Mommy will stay a few more minutes. Maybe we can read this story together and then it will be time for me to go. Stick to your timeline and include your child in the process, says Lietz. Empowering your child will make them feel more in control.

On the other hand, never sneak out. That's very scary for the child, says Lietz. Instead, once your child appears at ease in the classroom, you can say your good-bye discreetly. For example, if your child is busy coloring, Lietz suggests letting them know that you're excited to see the finished picture when you come back. You're keeping them engaged in what they're doing, while reassuring them that you'll return.

Parents, do your homework. Many teachers have sent a list of what the child needs for the first day of school, says Lietz. I've had parents show up and say, 'Oh, I completely forgot' or 'I've been so busy.' If your kid comes to school with nothing but his backpack and a lunchbox while the other kids have a packed cubby, he or she will feel less prepared.

Parents should let their child help pack the lunch, so the child has some ownership, says Lietz, reminding moms and dads that young children have small appetites, so don't overdo it. Sometimes children feel like a failure when they can't finish their lunch, she says. I've seen kids cry because of it.

If your child is tussling over a toy with another student, resist the urge to play referee. That's what the teachers are there for, says Lietz. Similarly, don't hover around your child introducing them to others students. Children need to recognize that they're independent and build their own skills and confidence, explains Lietz.

If you've been lax about bedtime, then it's time to start adhering to a schedule. Kids need eight to ten hours of sleep, says Lietz. If your child is getting less, then it will no doubt affect their behavior and performance in school. In fact, one recent study found that children who sleep less than nine hours a night or have irregular sleep patterns (going to bed at different times) struggle with basic skills, such as reading comprehension and grammar.

Don't let your kid leave the house with serious bed head and wearing yesterday's clothes—even if it's their favorite Captain America shirt. We ask parents to bathe their kids daily and send them to school in fresh clothes, says Lietz, noting that kids get sick easily and teaching personal hygiene is important. For the sake of their health and their reputation (no one wants to be labeled the messy kid), make sure your son or daughter shows up for class clean.