The best approach is to hunt down particular foodstuffs and consume them, rather than thinking in terms of restaurants. That includes fruits (start with blueberries and blackberries and then move on to the stuff you have never heard of), cheeses, arepas, empanadas, other baked goods, all forms of corn (“choclo”), and whatever they happen to throw your way.
“Have I had this yet?” should be your starting question, and try to get to a full slate of yes’s!
Don’t obsess over finding the best restaurants. You will end up with some excellent meals, but it is not the same as learning the local cuisine. That said, the dining scene is much improved since my last visit eight years ago. I didn’t have complete control over my time and meals, but can recommend Casa del Rey and Sauvage as both very good, without being convinced that they were the very best.