Q: My 14-year-old stepdaughter says she only needs seven hours of sleep, though her moods suggest otherwise. How much sleep do teens need each night, during the school year?

A: If her moods suggest otherwise, more than seven hours! Experts at the National Sleep Foundation (NSF) recommend that teens get 8 1/2 to 9 1/4 hours, every day of the week. (They recommend 10 to 11 hours for children ages 5 to 10 and seven to nine hours for adults.)

In a recent survey, A-Plus Advice Teacher Advisors said that if there were one back-to-school tip they wish parents would heed, it's "Make sure kids get enough sleep."

"Parents, please establish an appropriate sleep schedule and stick to it," says California educator Marianne Maloney. "Students are more sleep-deprived than ever. I blame our 'rushy-rushy' culture and the fact that they sleep with their smartphones. It's making them dumb!"

When teens don't get enough sleep, their problems can go well beyond the occasional cranky mood or dozing off in class.

According to NSF research, lack of good sleep affects brain development. It impairs students' ability to listen, concentrate and solve problems; it leads to forgetting important information like names and homework assignments. It decreases creativity. It can even cause acne, weight gain or other health problems.

The NSF's studies of teens found that those who sleep less than the recommended time are more likely to express unhappiness or sadness, feel nervous or hopeless about the future, or feel depressed.

Sleep gives the brain a "spring cleaning," says Penelope Lewis, author of "The Secret World of Sleep" (Palgrave Macmillan, 2013). It helps us filter out unimportant things weighing us down and creates "space" for new brain connections.

Technology can rob teens and children of good sleep, according to a recent study by University of Helsinki researchers. They found that the more children play on the computer or watch TV after school, the later they go to bed and the less they sleep on school nights. They found that having a TV or computer in the bedroom disrupted sleep, especially for boys. They recommend keeping TVs and computers out of the bedrooms of children and teens.

As you establish a sleep schedule for your stepdaughter, try to stick to it seven days a week, rather than allowing late nights and "sleeping in" on weekends and vacations. Trying to catch up on lost sleep can make for worse sleep, not better.

Consistency is key, says Dr. Kristin Avis of the Pediatric Sleep Disorders Center at Children's of Alabama in Birmingham. "It keeps their clock set so they can go to bed at a certain time, sleep well through the night and wake up well-rested the next morning."

While it's good for teens to participate in a broad range of activities, experts warn that clubs, sports and programs shouldn't come come at the expense of sleep.

Parents need to explicitly teach children and teens how to have healthy sleep. Sit down with your stepdaughter and review the healthy sleep tips here: www.sleepfoundation.org/article/sleep-topics/teens-and-sleep.

(Do you have a question about your child's education? Email it to Leanna@aplusadvice.com. Leanna Landsmann is an education writer who began her career as a classroom teacher. She has served on education commissions, visited classrooms in 49 states to observe best practices, and founded Principal for a Day in New York City.)

Q: We're looking for a preschool for our 3-year-old, Leon. My sister says, "Preschool is the new kindergarten, so prepare him for structure." Leon can hardly sit still! How can we find one that doesn't push him too fast?

A: While some preschools have a stronger academic focus than a decade ago, you can still find programs that match the preschool experience to a child's developmental level.

The educators who direct these programs know that the best starting point is where the child is, not what's in a workbook. Most 3-year-olds need to explore and play; they need time to wiggle, build, sing and shout.

David Elkind, a Tufts University child development expert, says too many preschools today hurry children with inappropriate expectations.

"While some children may be ready for academics," he says, "the vast majority of human brains aren't developed enough to truly learn reading or math concepts until they've reached the age of reason, typically at age 5 or 6."

When we push kids who aren't ready, "we risk killing their motivation for learning, for schooling and for respecting teachers," says Elkind, author of "The Hurried Child" (Da Capo Press, 2006) and "The Power of Play" (Da Capo Press, 2007).

Let your values and knowledge of your son guide you, says California-based early childhood educator Karen Hill Scott. To find a good match, review checklists for quality preschools.

"While a checklist won't make your decision for you, it's helpful to know what quality indicators to look for and how programs are defined," she says. "The National Association of Child Care Resource and Referral Agencies (www.naccrra.org) and the National Association for the Education of Young Children (www.naeyc.org) are useful resources."

Next, make a list of schools to visit. "Concentrate on the Three P's -- People, Program and Place," says Hill Scott. "Meet the director. The quality of the program rises or falls based on a director's competence. Can you relate to him or her? If the preschool were your workplace, would you want to deal with this person every day? Ask about the staff. What is their background? How long have they worked at the center?"

Any high-quality program, whether developmental or academic, should have a curriculum and a purposeful daily plan, says Hill Scott.

"During your visit, look for a clear connection between the activities and the curriculum goals," she says. "Do the activities encourage children to develop creativity, curiosity and problem-solving? Social and emotional skills? Are there abundant books, materials and play equipment? Will you receive regular communications about Leon's progress?"

Finally, consider the physical place. "The room has to feel right to you," says Hill Scott. "Cutesy architectural doodads are less important than having the sink near the bathroom so hands get washed, or creating a quiet corner so kids can curl up with a book. Look for the relationship of the space to safety and flow of activity."

After your visits, rank the programs in terms of the three P's. Then consider location, fees and hours of operation.

"You may not find perfection, but thanks to your homework, you'll find the best fit," says Hill Scott.

(Do you have a question about your child's education? Email it to Leanna@aplusadvice.com. Leanna Landsmann is an education writer who began her career as a classroom teacher. She has served on education commissions, visited classrooms in 49 states to observe best practices, and founded Principal for a Day in New York City.)

Q: In May, we gave my nephew, Brody, a substantial check for his high school graduation. He deserved it, graduating third in his class, but he's never thanked us. I adore him, but this drives me crazy. I believe good etiquette is as important as any academic skill. My husband says to let it go. Should I?

A: I'm in your camp. Knowing when to show appreciation isn't just good etiquette; it's an important social skill.

As an adoring aunt, you're entitled to give your nephew a helpful life lesson before he heads to college.

Forward to Brody this advice from Lizzie Post, the great-great-granddaughter of Emily Post and author of "How Do You Work This Life Thing? Advice for the Newly Independent on Roommates, Jobs, Sex, and Everything That Counts" (William Morrow, 2007).

Post says grads "absolutely have to be sending handwritten thank-you notes." They don't have to be long or complicated, only heartfelt. If the gift was cash, mention how it will be used -- such as putting it toward a laptop computer.

Post adds, "If the givers have also been a source of love and support throughout your life, mention in your note what they've meant to you. Close by sharing your hope that you'll see them soon."

While a handwritten note is proper form, grads can use creativity to get the job done. A friend of mine recently received a meaningful emailed "thank you" from a grad: a beautiful slideshow of photos of them together from past years. Each photo and caption triggered great memories.

Tell Brody that there's good evidence that expressing gratitude can make him a better, healthier person. Several studies have shown that being grateful can improve one's well-being and strengthen social relationships. It can enhance physical health, produce positive emotional states and even help diffuse stress.

Psychologist Robert Emmons says that when we make gratitude a policy and a practice, it "builds up a sort of psychological immune system that can cushion us when we fall. There is scientific evidence that grateful people are more resilient to stress, whether minor everyday hassles or major personal upheavals."

Adam Grant of the University of Pennsylvania and Francesca Gino of Harvard University found that gratitude has a profound effect that can bestow a big benefit to young people starting out in the world.

In a series of experiments, a fictional student named Eric enlisted advice via email from adults. The researchers discovered that when Eric expressed thanks, advice-givers were much more willing to help him again with advice and encouragement.

Grant and Gino also found that advice-givers weren't offering more help because it boosted their self-esteem, but because they appreciated being needed and felt more socially valued when Eric thanked them. Grant elaborates on this research in his book "Give and Take: A Revolutionary Approach to Success" (Viking Adult, 2013).

Let this all sink in with Brody. If he's the smart cookie he seems to be, he'll thank you for the rest of your life.

(Do you have a question about your child's education? Email it to Leanna@aplusadvice.com. Leanna Landsmann is an education writer who began her career as a classroom teacher. She has served on education commissions, visited classrooms in 49 states to observe best practices, and founded Principal for a Day in New York City.)