Read plenty of different books together. Immerse them in what they are interested in and have a variety available. Have fun with your voice, talk about what is happening, what they think will happen next and what they can see in the pictures. Asking 'Shall we read a book?' can result in a 'No' answer. Try choosing a book, sitting on the couch and start reading it out loud. It doesn't usually take long for them to come and see what is happening, especially if they are needing a rest.