I really can’t focus… I desperately need advice 😭

I can’t focus for more than 30 seconds before my mind zone out, and it’s ruining my life really. What techniques do you use to focus that works for you? My psychiatrist just refuses to acknowledge that I also have ADHD besides my autism so she won’t prescribe me any meds for it, so I need to rely on non-drug techniques. Please explain like I’m five what I can do.