This is my favourite marinade for steaks:

Take 3 tablespoons of sun-dried tomato paste, 1 teaspoon crushed black pepper, 2 cloves of garlic crushed, 1/2 teaspoon dried Oregano, 50ml of red wine, 100ml of olive oil.

Mix all the ingredients together. This will marinade 6 steaks at least. Leave overnight in the fridge. Cook on your BBQ. Enjoy

It is important to use the sun dried tomato paste, it has a more mellow flavour.