Combine olive oil, soy sauce, Worcestershire sauce, garlic powder, onion powder, black pepper, paprika, and salt in a bowl. Add the steak cubes and shrimp, tossing to coat. Cover and marinate in the refrigerator for at least 30 minutes, up to 2 hours for more flavor.
Preheat the grill to medium-high heat. If using wooden skewers, soak them in water for 30 minutes to prevent burning.
Thread the marinated steak, shrimp, and vegetables onto the skewers, alternating between the steak, shrimp, and pieces of bell pepper and onion.
Place the skewers on the grill and cook for 10-12 minutes, turning occasionally, until the steak is cooked to your desired doneness and the shrimp are opaque.
Remove from the grill and let rest for a few minutes before serving.