Staple Foods
Tortillas: flat bread typically made of corn, but sometimes made from flour
Beans: often served as a side dish with any dinner main course or as an ingredient
Rice: again, often served as a side dish or as an ingredient
Vegetables: varies by region, local vegetables are often included in dishes; some of the most common being both hot and sweet peppers, chilies, and onions
Regional Variations, Specialties, & Unique Dishes
North Mexico: this area is known for their emphasis on meat dishes
Southeast Mexico: known for their blends of spices and focus on fish or chicken-based dishes
Southwest Mexico: this region is famous for their moles (pepper-based sauces) and tamales (corn meal encased meats, vegetables, or cheeses)
Dining Etiquette
Eating in Mexico is a social event so the eating itself will always be severely delayed. If you're asked to meet at 6:00 at a restaurant, your acquaintances most likely won't show up until 6:30 or even 7:00. You'll then most likely wait another 30 minutes for a table and after you finally sit down, expect to have drinks and conversation for another half hour before ordering. This essentially means that meeting at 6:00 for dinner won't get food in your mouth until 8:00, if not later. This same time frame is fairly consistent if you get invited to dinner at a local's house; plan on arriving at least 30 minutes late or you'll be imposing on the host who still has plenty of work to finish.
Dinning takes so long in Mexico because it's meant to be enjoyed with family and friends; don't rush this process (instead eat a snack before going to dinner or eat a late lunch). Trying to expedite dinner can be seen as a sign that you want to finish dinner and escape your company. The primary motivation for dining with others is to socialize, not to eat.
Once you actually get to a dining room, wait until your host invites you to sit and once seated, never place your hands under the table. During dinner festivities, reserve the toast-making to men. Once you finally get to the food, wait until your host takes his or her first bite, then feel free to begin. As you close in on finishing your food, leave a little food left on the plate. Despite the protests of lunch ladies across the United States reminding you that there are starving children elsewhere in the world, finishing all the food on your plate is somewhat rude, especially in a home.
When eating out at a sit-down restaurant a tip of between 10-16% (before tax) is expected, but some restaurants catering for tourists already include a service charge in the bill so check before tipping. In bars a tip of 10 pesos ($1) per drink is standard.
Celebrations & Events
Most of the holidays and celebrations strongly associated with foods in Mexico are local festivals. Perhaps the most authentic of these local festivals is the Feria del Alfenique, which takes place in the city of Toluca. During this festival skull-shaped sugar candy is common. These same candies are also popular during Dia de Muertos (Day of the Dead), which takes place October 30, also known as All Saints' Day.
Cinco de Mayo (May 5) and birthdays and anniversaries are also common meeting occasions that require an over-consumption of food, including desserts.
Drinks
Mexicans drink just about every type of alcoholic and non-alcoholic drink depending on personal taste. Many sodas are popular as are juices, water, and other non-alcoholic drinks, all of which are popular and accessible.
Mexico has a number of popular alcoholic drinks, including the one they're synonymous with: tequila. Other well-known drinks include margaritas (which again uses tequila) and the mojito, which is made of fresh mint, lime, sugar and either rum or tequila among other ingredients. Lastly, Mexico has a few local beers, which are popular.
Although water is the world's most common drink, don't ever drink the tap water in Mexico; it is not known for its cleanliness or purity. Be sure to also avoid anything with ice as it may have been made from the tap water. Salads and fruits may have also been washed in the tap water so be careful with those foods as well. Some people argue it is safe, particularly in large cities like Mexico City; however illnesses are still very common from the water so avoid all tap water to be safe.