I have three rules for eating when travelling:
1. Never eat in a tourist zone. They always have a higher price tag and lower quality than they should or could! Up a tall building, opposite a touristy square, next to a landmark, then expect to hand over the moolah!
2. I use yelp and/or tripadvisor to find nice places that the locals hang out in
3. Check if the restaurant actually has some locals eating there!
I am amazed how often I have found amazing food in places just metres away from the tourists! At a third of half of the price.
Every time I break my three rules (which is not often), I regret it!