Studies haven't been able to show one treatment is better than all the others. They seem pretty much even. Physical therapy has been matched against steroid injections and a "wait-and-see" approach. There wasn't much difference in the results for each type of treatment.
A recent study compared a program of forearm stretching and extracorporeal shock wave therapy (ECWT) with stretching and sham ECWT. Again, there wasn't enough difference in results to say one was better than the other.
Certainly, avoiding activities that bring on your symptoms or make them worse should be avoided. This may be the best advice until more studies find out what really works.