After dropping off my 12-year-old daughter at her ballet class, her older sister, my 14-year-old surprised me with an observation.

"Look at her, mom," my 14-year-old said. "She's beautiful. She looks like a ballerina. See her long arms. See her long neck and how she carries herself."

I was pleased my older daughter was admiring her sister in such a loving way, without any hint of jealousy. Even though she didn't have the "dancer's body" that her younger sister had, she wouldn't trade who she was for anything in the world. She liked who she was.

"I wouldn't want to trade my personality for her body," she said.

What a win for a mom! My daughter was developing a good, positive sense of self. As a mom, I want most for my daughters is that they know their self-worth. Having a high self-esteem will help them through the highs and lows of life with confidence and happiness.

I've learned that we can start daughters on that path by communicating with them in a way that fosters self-confidence and respect for themselves and others. To do that, here are five phrases moms should avoid.

"I think that boy likes you"

Boys are wonderful! Boys are great! But interest from boys can give girls a false sense of self-worth. A girl should never think she has value because a boy likes her.

Instead of pairing up with just one boy, encourage group get-togethers. They are so much more fun and even better if you can help with hosting a party or outing.

Crushes and attraction from boys can sexualize girls at a young age. Most girls and young teens are too emotionally immature to handle the demands of a girl/boy relationship, and the breakup will be devastating to your daughter (and to you).

By helping your daughter develop talents and interests outside of boys, she will develop good self-esteem. She will have a feeling of self confidence that comes from knowing a new skill she worked hard to develop.

"You're so pretty (or smart or so anything else)"

I don't know a girl or woman alive that doesn't like to hear that they are pretty. The problem becomes when your daughter only identifies herself with being pretty. Soon she will start comparing herself to other girls. Then doubt sets in. Instead, compliment your daughter on the effort she puts into education, a sport or a talent that she enjoys.

In a study, led by Standford developmental psychology professor Carol Dweck, children labeled as "hard workers" performed better than children labeled as "smart." Dweck, who wrote Mindset: The New Psychology of Success, says children who are praised too often are less likely to take risks and accept challenges.

"Parents ... are not giving their children a gift when they tell them how brilliant and talented they are," she said. "They are making them believe they are valued only for being intelligent, and it makes them not want to learn."

"I told you so"

We all like to be right and we especially want our daughters to know that her parents are a great source of knowledge. However, there are times when it's better to keep silent and watch from the sidelines as our daughters evaluate for themselves the course of their life. They will figure it out.

If you don't let your daughters learn to make choices as children, they never will be able to as adults.

Humorist and writer Erma Bombeck said, "I love my mother for all the times she said absolutely nothing. Thinking back on it now, it must have been one of the most difficult part of mothering she ever had to do: knowing the outcome yet feeling she had no right to keep me from charting my own path. I thank her for all of her virtues but mostly for never once having said, 'I told you so.'"

"Are you going to eat that?"

I was a chubby child with a mother who struggled with weight issues. The focus on weight and food control in our home was torture for me. As soon as I was out of the house and out from other my mother's control of what I ate, my weight ballooned toward obesity. It has taken a good part of my adult years to get to a healthy weight, but I still see myself as a "fat kid."

Instead of making weight an issue in your house, foster good eating habits, have healthy foods available and get rid of junk food. Go biking riding, enjoy a hike and play a game a kickball with your daughter. These good habits will give them a lifetime of health and happiness.

"You failed"

As parents we might not ever say these word explicitly, but we inadvertently say it in other ways. "You could have done better." "You didn't try hard enough." "You're a procrastinator." We might even communicate it nonverbally by the tone of voice or the raise of our eyebrow.

Instead, give your daughter the chance to fail and help her see and feel that triumphing over something difficult can develop confidence to face future challenges.

JK Rowling spoke about the value of failure in her own life in a Harvard University commencement addresss.

"You might never fail on the scale I did, but some failure in life is inevitable," she said. "It is impossible to live without failing at something, unless you live so cautiously that you might as well not have lived at all - in which case, you fail by default."