There are probably as many "tricks" to cooking the best fajitas in town a there are self-proclaimed cookout or "carne asada" artists. You have to start with the source of the "lumbrita". Naturally, (pardon the pun) the number one choice is the indigenous mesquite as opposed to charcoal briquets. Other variables include the igniting agent, whether you rub onion on the grill or not, do you line the grill with foil paper. You get the idea.
Time after time, I've heard people comment that "so and so" really knows how to make a good carne asada. Is it the marinade? If you find yourself making "una carnita" pretty often, then this is second nature to you. But if you are a novice or if you do it very seldom, then I think Laredo needs the "experts" to get together and come up with Carne Asada for Dummies: Laredo Style. I probably would buy a copy just to have it in my Resource Library.