Raising a mentally strong kid doesn't mean he won't cry when he's sad or that he won't fail sometimes. Mental strength won't make your child immune to hardship—but it also won't cause him to suppress his emotions.

In fact, it's quite the opposite. Mental strength is what helps kids bounce back from setbacks. It gives them the strength to keep going, even when they're plagued with self-doubt. A strong mental muscle is the key to helping kids reach their greatest potential in life.

But raising a mentally strong kid requires parents to avoid the common yet unhealthy parenting practices that rob kids of mental strength. In my book, 13 Things Mentally Strong Parents Don't Do, I identify 13 things to avoid if you want to raise a mentally strong kid equipped to tackle life's toughest challenges:

1. Condoning a victim mentality

Striking out at the baseball game or failing a science test doesn't make a child a victim. Rejection, failure and unfairness are a part of life.

Refuse to attend your kids' pity parties. Teach them that no matter how tough or unjust their circumstances, they can always take positive action.

2. Parenting out of guilt

Giving in to guilty feelings teaches your child that guilt is intolerable. Kids who learn this won't be able to say no to someone who says, "be a friend and let me copy your paper," or, "if you loved me, you'd do this for me."

Show your kids that even though you feel guilty sometimes—and all good parents do—you're not going to allow your uncomfortable emotions get in the way of making wise decisions.

3. Making kids the center of the universe

If you make your entire life revolve around your kids, they'll grow up thinking everyone should cater to them. And self-absorbed, entitled adults aren't likely to get very far in life.

Teach your kids to focus on what they have to offer the world, rather than what they can gain from it.

4. Allowing fear to dictate choices

Although keeping your kids inside a protective bubble will spare you a lot of anxiety, playing it too safe teaches your child that fear must be avoided at all times.

Show your kids that the best way to conquer fear is to face it head-on, and you'll raise courageous people who are willing to step outside their comfort zones.

5. Giving their kids power over them

Letting kids dictate what the family will eat for dinner or where the family goes on vacation gives kids more power than they are developmentally ready to handle. Treating kids like an equal, or the boss, actually robs them of mental strength.

Give your kids an opportunity to practice taking orders, listening to things they don't want to hear, and doing things they don't want to do. Let your kids make simple choices while maintaining a clear family hierarchy.

6. Expecting perfection

Expecting your kids to perform well is healthy, but expecting them to be perfect will backfire. Teach your kids that it's okay to fail. It's fine, and normal, not to be great at everything they do.

Kids who strive to become the best version of themselves, rather than the best at everything, won't make their self-worth dependent upon how they measure up to others.

7. Letting kids avoid responsibility

Letting kids skip out on chores or avoid getting an after-school job can be tempting. Afer all, you likely want your kids to have a carefree childhood.

But children who perform age-appropriate duties aren't overburdened. Instead, they're gaining the mental strength they need to become responsible citizens.

8. Shielding kids from pain

Hurt feelings, sadness and anxiety are part of life. Letting kids experience those painful feelings gives them opportunities to practice tolerating discomfort.

Provide your kids with the guidance and support they need to deal with pain so they can gain confidence in their ability to handle life's inevitable hardships.

9. Feeling responsible for their kids' emotions

Cheering your kids up when they're sad and calming them down when they're upset means you take responsibility for regulating their emotions. Kids need to gain emotional competence so they can learn to manage their own feelings.

Proactively teach your child healthy ways to cope with their emotions so they don't depend on others to do it for them.

10. Preventing kids from making mistakes

Correcting your kids' math homework, double checking to make sure they've packed their lunch, and constantly reminding them to do their chores won't do them any favors. Natural consequences can be some of life's greatest teachers.

Let your kids mess up sometimes and show them how to learn from their mistakes so they can grow wiser and become stronger.

11. Confusing discipline with punishment

Punishment involves making kids suffer for their wrongdoing. Discipline, however, is about teaching them how to do better in the future

Raising a child who fears "getting in trouble" isn't the same as raising a child who wants to make good choices. Use consequences that help your kids develop the self-discipline they need to make better choices.

12. Taking shortcuts to avoid discomfort

Although giving in to a whining child or doing your kids' chores for them will make your life a little easier right now, those shortcuts instill unhealthy habits in your kids for the long term.

Role model delayed gratification and show your kids that you can resist tempting shortcuts. You'll teach them they're strong enough to persevere even when they want to give up.

13. Losing sight of their values

Many parents aren't instilling the values they hold dear in their children. Instead, they're so wrapped up in the day-to-day chaos of life that they forget to look at the bigger picture.

Make sure your priorities accurately reflect the things you value most in life, and you'll give your children the strength to live a meaningful life.