Fairly conservative is the rule. As usual, swimwear is appropriate only at the beach or pool. Small towns tend to be more conservative. In the cities appropriate attire may range from very casual to suit and tie. Some, not all, dishes are hot and spicy.
Corn is a staple of the diet.
The tortilla, a thin pancake made of coarse cornmeal appears in many guises. Mexicans make a variety of outstanding soups, breads, and desserts. Mexico produces a number of good beers and some local wines are quite good, too. Nightlife is determined by location. The cities and resorts will have enough activity to satisfy most any interest.