What would be a good way to convince my doctor i have adhd?

ADHD diagnosis: There is no legitimate reason to convince a doctor about a diagnosis. See a person competent to make the diagnosis, including referring you for testing. Not meaning to offend, it you are simply trying to get a doctor to prescribe stimulant therapy, that is not a healthy goal. If you think you have adhd, see a specialist to address that.

History and exam: If you doctor/mental health professional is competent, a clear history of the multiple problems with inattentiveness and/or hyperactivity impulsivity that add'ers have, coupled with a specific review of symptoms, coupled with an interview and "mental status exam" should get the diagnosis. Objective computerized testing can also be performed. For competent doc, "convincing" shouldn't be required.