It can be quite dependant on the situation. Start the APU? At 40,000ft? Are we on final approach or just passed V1 on t/o roll? Sometimes the RAM is the better option over the APU, or even your only option.
But always go threw the checklist if the situation allows, then determine the cause of the failure and start considering your options. Once again if the situation allows call the controller stating your problem and any other important information, and what your intentions are. Thats when the controller starts to sweet too, depending on the situation his workload will increase alot also, keep radio transmision short both ways.. Then if practical go threw the inflight restart checklist, and if theres no other option just keep going threw that checklist... If of course you were as bright as the pilots of that A330 over the indian ocean or something you might start cross feeding fuel right outa your aircraft so youd be gliding.. In which case youd extend the RAM and fly your optimum glide speed and head for the nearest suitable airfeild.
Unless of course your glider is flying by ETOPS, then just get the toggs on get ready to go for a swim
Experiance, good training, comman sense and pursivearance would be most important to deal with such a situation.
James