Personally, I don't like my steaks marinated. With that said, I am forced to prepare certain items a certain way for others. I prefer this marinade with chicken and salmon, but it works really well on beef too.
1/2 cup pineapple juice
1/3 cup Captain Morgan rum
1/4 cup soy sauce
2 tablespoons brown sugar (packed)
1 tablespoon ginger, grated
2 cloves garlic, minced
1/2 teaspoon crushed red pepper
3 tablespoons olive oil
1/4 cup minced spanish onion
Juice of 1/4 of a lemon
Add "about" to all of the measurements... hahah I suck at them. I eyeball most everything and add to taste. Put whatever you are marinating in a ziplock bag and then the marinade. Put it in the fridge for at least 4 hours.