You will need:1/4 cup olive oil
1/4 cup soy sauce
1/4 teaspoon garlic powder
1/4 teaspoon black pepper
3 Tablespoons ketchup
1 1/2 Tablespoons vinegar (whatever kind you like) Combine all ingredients together in a large container, or mix everything together inside a very large ziploc bag. Add meat and marinate 24 to 48 hours in refrigerator. Turn meat over occasionally for even flavor.
This marinade is great for venison, also sirloin and round steaks, but feel free to be creative. This is a very basic recipe.