Katherine Schwarzenegger Pratt knew that she wanted to write a children's book about sisterhood after she had her oldest daughter, Lyla.

Her book, titled "Good Night, Sister," celebrates the special bond between sisters, but also acknowledges that you don't need to have a sister to appreciate its message.

She explains that her close relationship with her own sister has informed the way she raises her daughters.

Here are some of her tips to combat jealousy and rivarly:

"It's about allowing kids to be celebrated for their own individual interests, separate from each other."

"So much (of my upbringing) was done really gently and lovingly and not comparing the two (of us)"

"Never using the second child as an excuse not to do something with the first child."

Read more here (via TODAY)