Whisk together the oil, lime juice, garlic, Worcestershire sauce, brown sugar, cumin, salt, black pepper, and red pepper flakes in a large bowl or baking dish. Alternatively, combine them in a jar if making in advance.
Add up to 1 ½ pounds of steak, chicken, shrimp, or vegetables, toss to coat, and cover.
Refrigerate chicken for 30 minutes to 8 hours and steak for 2 to 8 hours. Marinate shrimp and vegetables at room temperature for 20 minutes.
Remove from the marinade and pat dry with paper towels before cooking.