What worked for me is:

- First stabilising by avoiding all unnecessary usage

- Avoid wrist straps, they make it worse because your muscles will atrophy

- Learn stretching and strengthening exercises from a physio

- Use a Kinesis Advantage and a trackball

- Avoid pronation

- Start rock climbing, to make my arms/wrists strong

Since then, I rarely have pain.

You can get short term relief from dunking your wrists in ice cold water (reduces inflammation).