i've had the same issue when i started. Some spy tools out there to find competitor examples of ads but ultimatly i just followed the script and template that Brian teaches in the course and it helped me make several iterations. I'd recommend you'd start there. I've closed some deals this way as well.
Good way to see whats working for them is obviously how long the creative has been running for (even tho thats a bit speculative it makes sense logically, they wouldn't spend on an ad for 3 months that doesn't perform [if the business doesn't suck])