Salaries in tourism and the hospitality industry (including restaurants) are often very low; people may depend on receiving tips to supplement their basic wages. So if you receive good service, it is good to show your appreciation by giving a tip.
In restaurants in Mexico, it is common to leave a tip of approximately 10 - 15% of the total of the bill. In some restaurants, service is included, particularly if you're part of a large group, but this is not usually the case. Always check the bill to see if service is included or if there are errors in the calculation. If a service charge is included, you may choose to tip extra for superior service. In food stands and low-cost eateries, it is not customary to leave a tip, but if you do leave one, it is usually very much appreciated.
Bellboys and room-maids (per night) in hotels should be tipped around 25 - 50 Pesos, depending on the destination, hotel class, and quality of service. If you are pleased with your tour guide, it is appropriate to tip 10 to 20% of the cost of a day tour. For touring holidays of multiple days, tip the tour guide a minimum of two or three dollars per day, and coach drivers one dollar per day. It is not customary to tip taxi drivers unless they assist you with your luggage.
Keep in mind that leaving a tip is important, but a smile and a "gracias" can be just as important in showing your appreciation!