If using store-bought green curry – keep in mind- all brands vary in heat and salt levels. You may not need as much salt and perhaps less fish sauce– so add both to taste. Bump up the flavor with sauteed chopped shallots (saute first, then stir fry with the curry paste) and add kefir lime leaves and a few slices of galangal to the curry sauce. My favorite brands are Maesri (in a can) and Mae Ploy – available at most Asian Markets. Maesri and Mae Ploy can be quite spicy so start off with 3-4 tablespoons, until you are familiar with their spice level. You can always add a little more in the end.
If substituting chicken for the tofu, thinly slice it (1/4 inch thick slices) and add it directly to the stock or broth or feel free to poach it separately in salted water or broth for just a few minutes before adding to the curry sauce.