Choose books in which that the children are interested. The best way to ascertain this is to ask. Polling the class or group of children about interests can ensure that the material will be something that will grab and hold their interest. Consider books involving identifiable situations about school or how to deal with problems and situations third-graders face. Also, chapter books with interesting characters, quick moving plots and descriptive language are best.
Engage the children by asking them to use their imaginations while you read. Inquiring how they would deal with the subject matter in the book or asking how they feel about the material pulls children in and can help hold their attention.
Take turns reading. Whether you are reading with a group of third-graders or with one child, alternating reading can make the child or children feel a part of the reading process and help to stay focused on the material.
Summarize or skip through parts of the book that might be above the heads of your audience. If you notice that you are losing the attention of your audience, you can summarize portions that seem to drag. You are not changing the story, but trying to maintain the integrity of the material without losing your audience.
Leave them wanting more. End your reading sessions at a cliff-hanger or intense part of the story so that the children are eager to begin the next session.