Very often when people start reading a book with a child, the adult will open the book, maybe read the title, and then start right into the story. There's a lot to be gained by talking about the book before it's even opened.
When I read a story with a child, we'll look at the cover of the book, the picture on the front. We'll talk about who the author is, and who the illustrator is, or who it is that made the pictures. I always like to ask the children, "What do you think this story is going to be about?" It gets the juices flowing in their brains. Talking about the author and the medium used by the illustrator helps children learn which authors they like and would like to hear from again.
As we go through the book and look at the first page, I'll read the words and ask them if they know what a word means if I think they might not be familiar with it. Sometimes I'll ask them what they think is going to happen next in the story before we turn the page, and sometimes I'll ask them what's happened so far in the story.
If the story is predictable, as some Eric Carle books are, it's easy to omit the last word from a line and let the children fill it in. They love it.
When the story is over, children will always have something to say to relate the book to their life. In reading lingo, it's called, "Text to self connections". If you take the time to listen to what the children are saying, they are making some very important connections and sometimes they might even surprise you. :)