Dating with one brother can be hard enough, but what if there are 18 other siblings to contend with? That's the life of the four eldest Duggar daughters, who have entered their dating years, Duggar-style.

Jana, 24, Jill, 22, Jessa, 21, Jinger, 20, and the rest of the Duggar gang discussed what it's like coming of age in this highly watched family on "Good Morning America," sharing tips and tricks for finding a partner from their new book, "Growing Up Duggar: It's All About Relationships."

"Courtship is a new season of life. It's exciting," Jessa said. "We call it dating with a purpose and not just frivolous, really considering the person as a potential life partner."

Jill agreed, saying, "We talk about what we're looking for [in the book]. Not just, 'Oh, he's a cute guy.' But the heart of the matter. Is he going to be a good father? Is he slow to anger? We have a list in [the book] that helps girls think deeper than just the surface."

The family is preparing for the next season, which premieres April 1 on TLC and will show the dating lives of the four girls. And it wouldn't be a Duggar season without some more child speculation.

"We would love to have more children but we're waiting to see," mom Michelle said. "You'll have to check in the next season."