The easiest way to enhance the flavor of an ingredient is to marinate it. Marinating is nothing more than steeping a piece of meat, fish, or vegetable in a flavored liquid for a while. I suspect that you can marinate any food at all, since I've also succeeded with cheese, leafy greens, and fruit. The secret to marinating is simply in the marinade -- the liquid -- that you make.
Think about what you want the food to taste like after it's been marinated. If you want your fish redolent of lemon and fresh herbs, you'll want to add lemon zest and chopped herbs to oil. If you want tenderloin that's richer and more succulent than it should be, plain red wine will amaze you. And if you have some carrots you want to enhance, try a thin version of a salad dressing.
You can add almost anything to the marinade. In India, marinating meat in yoghurt or spiced milk is not uncommon, and it has the advantage of tenderizing chicken wonderfully. Acids, such as citrus juices or vinegars, can chemically "cook" proteins, resulting in succulent, sushi-like fish. And tofu absorbs any flavor like a sponge, tolerating syrupy marinades created from every sauce sitting in the refrigerator and each ageing tin of spice in the cupboard.
The length of time you marinate is flexible, but there are some guidelines. Red meats can handle -- and even benefit from -- several days of soaking. Fish being steeped in an acidic marinade, however, only needs a half of an hour. Vegetables, particularly if they're raw or only lightly cooked, can be refrigerated in their marinades and grabbed out of jars when needed. Most overnight or temporary marinades should be refrigerated unless you only have a few hours, in which case you can leave them at room temperature. Heavy-duty zip-closure plastic bags are the ideal containers, since you can mix the marinade right in them, then make sure that everything inside is in contact with the liquid.