In a small bowl, combine the chili powder, cumin, salt, garlic powder, oregano, paprika, sugar, and red pepper flakes.
In a large bowl or baking dish, drizzle up to 1 ½ pounds steak, chicken, shrimp, or vegetables with vegetable oil and rub with the fajita seasoning. Let steak and chicken sit at room temperature for 30 minutes before cooking. Shrimp and mushrooms can be cooked right away.
