One of the pleasures of gardening is putting your plants "to bed" at the end of the season. This preparation for the winter varies depending on the climate you live in and the type of herbs in the garden.
In milder warm climates there are fewer tasks to complete. The perennials may be utilized all winter long with careful snipping but don't strip off too much or you will jeopardize the overall health of the plant. Rake out the rest of the bed removing any fallen leaves or sticks and weed around your plants. Edge the beds or repair any edging materials then mulch the beds and remove any ornaments that are better off in your garage for the season.
Colder regions require much more preparation to overwinter your herbs safely. You need to still rake out your beds to remove the debris and store your ornaments. But you also need to trim your hardier perennials back, taking off about half the new growth. If you wish to bring the less hardy perennials inside for the cold season you should also cut them back and put them in the autumn. Don't bring them in yet but leave them on your porch or somewhere enclosed and still sunny. You can also trim the root and wait for feeder roots to form before you pot them.
When the weather turns cold bring them inside but remember your indoor air is a great deal drier than the outdoors due to the heating. Some herbs cannot handle this switch well without the preparation and their leaves will all fall off in shock. You must keep the air humid around your plants so it is prudent to habitually mist your herbs with water. The herbs need to be in a sunny area preferably facing south.
When the ground freezes completely you should mulch around the herb plants left outside, try to use natural materials if possible such as straw or untreated bark. Using organic mulch is great two fold because it protects your plants and breaks down in the spring to provide substance to your soil.
You might find that many herbs over winter inside well to provide a great indoor garden containing chives (which will come back if left outside), basil, lemon verbena and sage. Rather than pot and unpot these herbs every fall it can be effective to simply keep them in the pots and bury the pots up to the rims in the garden to give the appearance of being in the ground. You can also just leave the pots in a wonderful small container garden on your porch or create a space in your garden for the pots to rest during the summer.