Supplements sold for tinnitus have not been shown to work in good trials. Sound therapy is set just below the level of the ringing, not to drown it out.
If you have hearing loss, a hearing aid brings back the outside sounds your brain was straining for. Most brands we fit add a tinnitus sound programme, and many let you adjust it from a phone app. See hearing aids for how the trial works.
Tinnitus feels worse when it is linked to worry. Understanding what the sound is, and that it is not harmful, takes away much of that alarm. We use CBT-style techniques to break the cycle of noticing, worrying and noticing more.
Caffeine affects some people and not others, so watch your own pattern rather than cutting everything out.