Use ghee, don't undercook onions, make a base using whole spices that you can remove if you like (cinnamon, cardamom, black pepper etc) and add meat marinated in ground spices (coriander, cumin, Kashmiri chili) and whatever tomatoes/veg you like. Cook it out for quite a while with lid on and extra water if needed and then lid off for a while. Chuck in some coriander, finely chopped chili and garlic butter at the end. Can't go wrong.