There isn't just one type of autism and depending on the type the child has been diagnosed with, the therapy to help the child will be a little different. However, many caregivers agree, nearly all children with autism thrive on sensory integration. Sensory integration is simply learning to combine our given basic senses (sight, smell, touch, hearing and taste) to coordinate and interpret the world around ourselves. This is something most people do effortlessly as they grow up, however autism can rob a child of the ability to do this automatically and it must be learned.
One way it can be learned is through play. There are a large number of sensory developed toys that can enrich the lives of autistic children and help them learn to coordinate what they are feeling, seeing, etc; and interpret it to the world around themselves. Toys that encourage movement, touching, or change as they are played with are all good choices to use. Tactile bars are a great example of sensory play. These bars have several different textures on them and the children can feel of them and learn the different ways that various items "feel".
The sooner the child starts sensory integration, the sooner you can start seeing results. Make sure that your child has tactile toys outside the therapist's room and keep his mind working and growing through sensory stimulating play.