How can I help my 8 year old son with ADHD?

Q. I’m looking for advice on how to deal with a temperamental eight-year-old boy who can be really challenging. He can be impulsive, inattentive, disobedient and unable to accept responsibility for bad behaviour. We took him to a psychologist who said he had significant ADHD/ADD symptoms, which fits with what we were experiencing. We decided not to pursue this further as we did not want to put him on medication. But we are looking for advice on how to manage his behaviour.