Even if you know that reading to your child is most effective if the child and you are both reacting to the book, it can still be difficult to think about how to engage your child. One effective method, explained more fully here, is to use a brief sequence of exchanges to solicit responses of greater depth.
The sequence is called PEER, and stands for Prompt, Evaluate, Expand, and Repeat. In Prompting, the adult asks a child a question about something that they see or have just had read to them. The adult then Evaluates, considering what the child has said. Next, the adult Expands upon the child's statements, adding new information. Repeat the prompt from the beginning to see how the child has adapted the new information.
Through a quick interaction, the child gets to test the edge of their understanding, learn a little bit more, and gain confidence in their abilities. It also gets the adult in the habit of engaging the child in conversation about reading, which is great for the long-term development of the child's reading habits.