Tell your server to hold the cheese on the bean burritos and ask for pinto beans rather than refried. Instead of having a bean burrito rolled in a flour tortilla, ask for the kitchen staff to use corn tortillas.
Look beyond the fatty tacos and rellenos--think of a sizzling platter of grilled chicken, onions, red and green peppers and tortillas. Ignore the sour cream and guacamole and load your fajitas with pico de gallo, which is chopped tomatoes, onions and chiles or jalapenos. Spoon the pico de gallo on top of the chicken, peppers and onions, roll up the tortilla and you can enjoy a low-fat Mexican food that is still loaded--with taste, not fat or calories.
Order soft-shell tacos, not hard-shell. While you’ll have to be careful not to let the fillings spill into your lap because the tortilla is so soft, you are leaving the fat behind. Besides, it’s easier to clean meat, lettuce and tomato off your lap than it is to lose the extra calories the next day. 
Have you ever heard of a mariscos restaurant? Marisco is Spanish for “seafood." Some, although not all, of the foods made at a mariscos restaurant is grilled, not fried. Think grilled tilapia with chopped garlic (pescado al mojo de ajo). Pescado Veracruz is grilled fish topped with grilled vegetables. When you couple this with baked potato chunks with the skin and rice, this is a meal that fills you up. These restaurants also serve fish tacos, made with grilled fish, coleslaw (easy on the mayonnaise), chopped tomato and spicy salsa), shrimp cocktail--coctel de camaron and seafood soups. Another good choice is tacos carne asada, or grilled pork tacos. The meat is folded into soft, not fried corn tortillas and accompanied with pico de gallo, a slice of lime and avocado slices. A healthy lettuce and tomato garnish and orange slice complete this meal. Pair this with iced tea, water, coffee or a glass of horchata, and you can shave calories and still walk out feeling satisfied.