One of the ways is to give them a reward if they finish a book. The parent could choose a book and give them the goal to finish it in a certain amount of time(one week) and give them a reward if they finish it that time. Another way is to go to the library with them. There, they have a range of books to select from. They could choose any book they wanted. There are many other ways as well, including getting them to write about what the book is about, but these are just a few of them.
Several ideas: read to them from their first days! Read exciting and interesting books, put on funny voices for characters, make your voice interesting. Reading to a child is an art but if you start when they are a few days old, you'll learn the craft together :)
With older children who have lost (or never had) an interest in reading, audio books are a great idea. Professional readers and great stories. Read in instalments so they want more . Enjoy the experience yourself. Don't let them be seduced by television.
By reading to them from the very beginning. When my kids were little, I mean like 1 year old, I started out with simple books as a part of our bedtime routine. They are now 5 and 6 and love to just pick up a book and read it for fun, even the 5 year old who isn't quite yet at school.