Depending on where you are and who you ask, the michelada can be quite different.
The spicy beverage of Mexican origin is generally considered to consist of lager beer with lime, tomato or clamato juice and various spices. The spices will very as well, but typically include black pepper, hot sauce and worcestershire. The michelada is served in salted rimmed glass, garnished with a lime.
Variations of the michelada in Mexico will include clam juice as well. The term michelada is almost always used interchangeably with a chelada, but a chelada is technically only lager beer with lime in a salt-rimmed glass.
As expected, a michelada pairs best with a Mexican lager and most establishments will ask which one you prefer upon ordering. A michelada can be served on ice or without.
In the United States, you will most often find micheladas made with tomato juice, lime and house spices, but the variations are endless. Each establishment will have their own take on the michelada and the adventure of finding your favorite is all part of the enjoyment.