Put books in the toy box or wherever you keep toys. Children spend a lot of time in both the kitchen and the bathroom. Put books there. The key is to put books wherever they can be visible and accessible. This increases the likelihood that the books will be picked up and used.
Babies can have books in their cribs and play pens.
Use waterproof books in the bathtub. When books are found only on carefully arranged shelves children tend to get the idea that they need to be kept nicely and will leave them on the shelf, rather than take a risk of damaging them. If you make the books more available it sends children the message that books are part of their everyday lives and are meant to be used. Children who grow up with books know that books are important. Because children tend to copy adult behavior, they need to see adults in the home spending time reading and writing.