Just a simple rule: Eat where the locals eat.
It´s as easy as that.

We did the same last year when we went to Sardinia.
We were looking for a restaurant or something like that for lunch.
And found a place where no foreign cars where parked.
Great food, good prices, everything was awesome.

So be brave and go somewhere, where not all the tourists go.
And you´ll be very positive surprised.