It was a crowded flight on a hectic day not too long ago when Deborah Norville heard a "whoa!" uttered by the woman sitting next to her.

"I looked out the window and it was the most spectacular sunset," says the "Inside Edition" host, describing the vivid reds and golds that painted the sky.

"I was so grateful for that sunset, but I was also grateful for that lady," she recalls. "At that moment, worrying about rushing to the airport, getting through security on time, it all melted away."

Norville was practicing what she covers in detail in "Thank You Power: Making the Science of Gratitude Work for You" (Thomas Nelson, $19.99). It's in 13th place on the New York Times hardcover advice best-seller list.

In the book, the 49-year-old television host and mother of three reports on research done at places like the University of Michigan that indicates showing gratitude can help you be healthier, happier and better equipped to deal with stress.

The power of thanks goes deeper than the polite, almost automatic response you give when someone opens a door or delivers a message. Norville describes it as an active, aware process: "It's the knowing and the recognition, the acknowledgement and the gratefulness for the benefit you've received."

It's also something you can grow through practice.

"We all know if we do sit-ups, that flabby tummy is going to go away," she says. "But how many of us really do that every day, get ourselves on the floor and do the sit-ups? It's the same thing. It requires discipline and it requires regularity, according to the studies I report, to be effective."

As part of her routine, Norville jots down things to be thankful for in a small green notebook she carries with her.

"The things I find that I write down, more often than not, are people," she explains. "It's either people or moments," not material things, that earn a mention.

In the book, she offers exercises and tips for honing gratitude and shares tales of people who've used it to cope with life-altering experiences.