1) Get the right diagnosis: The tendon is often the cause of the pain if it is localised to the lateral hip. The bursa is often secondary but can be involved. The treatment for each is different.
2) Aggressively offload from ‘compressive’ positions: this includes all positions where the gluteal tendons are squashed against the bone they insert into on the outside of the hip. This compression contributes to the pathology and pain. It can be minimised by avoiding all movements where the leg crosses the midline – eg crossing your legs, sleeping on your side with your painful hip on the top
3) Limit walking until symptoms are under control: often walking is an aggravating factor, especially in people who are not active in sport. Even walking for 20-30 minutes can keep you in a symptomatic/painful phase. Limiting walking in the short term is always difficult but very useful to bring symptoms under control and allow good quality loading.
4) Load the muscle and tendon in non-compressed positions: again the thigh should not cross the midline so see an experienced clinician who will give your the right exercises at the right time.