Among the first things I learned to make as a prep cook were bouquets garni—little bundles of herbs and spices tied together with twine or wrapped in cheesecloth. I added these packets to soups, stocks, sauces, braises, or any other dish with a lot of liquid and a long simmer. My restaurant days are over, but I still use this technique at home. A bouquet garni (pronounced boo-kay gahr-nee) keeps all my herbs together, making them a cinch to remove (so I don't have to fish for the bay leaf before serving a stew, for example).
Parsley, thyme, and bay leaf are the standard trio. I use four or five parsley stems, a sprig or two of thyme, and a bay leaf.
Other aromatics can give your dish a more complex flavor. A few whole cloves add a touch of warmth and sweetness; a strip of citrus zest enhances meat-based stews and braises; a sprig of rosemary, sage, or savory sets a Mediterranean tone; and a garlic clove is a welcome addition to almost any selection of herbs.