Watch and talk to the child to better understand his or her developmental level. Although there are typical ranges that children of this age (between three and six years of age) fall into, keep in mind that each learner is an individual. Observe the child, listen to what is said or even review classroom work such as worksheets, drawings or writing. This will hep to paint a better picture of the child's actual level.
Integrate what you observe about the child with commonly accepted developmental abilities for preschoolers. Those under five can typically speak in complete sentences, engage in pretend play and understand basic sequences. Older preschoolers can use more complex or longer sentences, create their own imaginative stories and understand time sequences.
Preschoolers are learning to interpret visual symbols, and can learn through picture books that include both images as well as print letters/words. Look for books that have vivid illustrations or photographs that tell a story, engage the imagination, large letters to see and have a simple storyline that is easy to follow. For example, Maurice Sendak's classic book "Where the Wild Things Are" provides the child with a well illustrated picture-like storyline in a creative way.
Look for books that reflect a variety of different types of people, cultures and communities, as well as basic concepts that preschoolers are learning. Age-appropriate concepts may include the alphabet, colors, numbers, shapes, community helpers, animals or emotions. This makes reading meaningful to the child and will help him to engage in the story. For example, Eleanor Schik's, "Navajo ABC" includes information about the Native American culture and provides the child with a chance to learn about letters.