They’re repping a particular regional cuisine
Any indication that taqueria owners are slinging tacos and other dishes from their home state or other regional specialties is a promising one. Are the words “Barbacoa Roja estilo Sinaloa” splashed across a taqueria window? Odds are the makers of the pork-and-beef barbacoa are from the northwestern state of Sinaloa. (Estilo means “in the style of.”) They might also have goat birria, red and earthy from chiles, cinnamon and cloves. Is that birria de res (beef)? You might have stumbled upon a Zacatecas-style joint. What’s up with that taco dorado de camaron? It’s a shrimp-stuffed fried taco specialty out of San Juan de los Lagos in the state of Jalisco.
However, scarf enough tacos across your hometown and you’ll notice a glut of Mexican restaurants and taquerias with names including “Jalisco.” Not all of them serve Jalisco cuisine. Rather, the frequent use of the name has to do with Jalisco state’s being considered the soul of Mexican culture. It’s from Jalisco we get mariachi, pozole, and tequila. Be wary. That goes double for “DF-style” spots. DF, or Distrito Federal, the Mexican analog to DC, is shorthand for Mexico City, whether used in conversation to refer to one’s home or to refer to the cuisine. In cases of the latter, DF is usually code for generic tacos -- the same examples found in taquerias across the world: carne asada, pastor, pollo, lengua, and chorizo -- or, as I like to call them, pork-beef-chicken. (More on that later.) As the capital, Mexico City draws people from across the country who in turn serve their own regional specialties.
So again, look for for words or phrases beyond “estilo-PLACE NAME.” Search for specific dishes. If you see suadero or cabeza al vapor, two dishes that can claim actual DF provenance, you might just have a true Mexico City spot before you. Does the taqueria claim to trade in food from Puebla? Look for tacos arabes. You can do this even before entering the taqueria. Just look for the art on the exterior of the building -- what I call "tacos illustrated."