Reading
Try reading "Daniel isn't Talking" by Marti Leimbach, it is a (99%) true story, her story, just with the names of people changed. There are many more books available about autism than there were in the past. Start to educate yourself. You're going to have to find out what is going to work for you and your child. The more informed you are, the better decisions you can make. Read some good theory based parenting books. (Parenting with Love and Logic & Systematic Training for Effective Parenting (STEP) are a couple.) The strategies may need to be modified for your particular child, but it will be helpful to have a good understanding of some good principles for parenting.
Stimulation
Feeding
Activities
Stimulation
Some kids respond well to vestibular stimulation. (motion) Pulling the child on a scooter board (put a helmet on the child) or swinging in a hammock may help to calm the child down. There are special swings you can buy which can be set up in a door jam. (Great for rainy days when you can't go outside.) Tactile stimulation may help calm a child down. Playing with water or sand are great developmental activities for any child. Clay works well. (As long as your child doesn't eat it.)
Feeding
Make sure you feed your child on a regular schedule. Nothing will make a child with developmental difficulties cranky like not getting lunch or dinner on time.
Activities
Activity using large muscle groups helps regulate mood. My son was having a very difficult time with behavior issues in school until an occupational therapist suggested a break every two hours to do some pullups or running. (He was about 7 years old.) The outbursts dropped dramatically. When behavior started to improve, the lenght of time between breaks was gradually increased. When behavior was difficult again, the activity breaks were increased. Taking the kids for a walk or to the park may help behavior at home.