If you have the inclination, growing your own herbs is the easiest way to always have some on hand. Basil, mint, rosemary, sage, thyme, marjoram, and oregano are all fairly easy to grow, even indoors on a windowsill. If it is not practical to grow your own herbs, buy them as you need them. Most supermarkets now have a pretty good selection year-round. Keep herbs in the refrigerator in a Ziploc bag. Wrapping them in damp paper towels keeps the leaves too wet and causes them to rot faster. I always strip the leaves from the stems and chop the leaves just before adding them to what I’m cooking. Chopping herbs ahead of time causes them to turn brown and lose their fragrance.