- Cut stimulant use (coffee, energy drinks) and alcohol
- Drink plenty of water
- Check blood pressure
- Talk to a dentist and check if you grind teeth or suffer from jaw stiffness
- Supplement Magnesium (chelated/glycinate, 300mg/day)
I’m ignoring issues of the ear canal (wax, secretions) since you mentioned it.
Studies point to tinnitus being either caused by changes in blood supply on the inner ear, of neurological origin or trauma. These are all measures I took and greatly improved my case (and when I neglect one of those, it comes back).