Herbs are generally grown indoors during the winter months, although some folks maintain a 'kitchen garden' year round. Oregano makes an awesome addition to any indoor or kitchen garden.
Indoor oregano has the same needs as oregano grown outdoors. The plants thrive under the same conditions, temperature, humidity, nutrients, moisture. At night, temperatures near a window will generally plummet ,the same happens in nature. Try to keep the plants from coming in contact the glass to prevent it from becoming overly chilled in colder weather.
Dry forced air, from heating systems, is hard on any herbs, A misting 2 - 3 times weekly will help or a humidity tray in the vicinity.
Well-drained soil with a pH of 6.5 to 7.0 is best. Sand, peat moss and perlite such as found in most potting mixes is best. It doesn't need a lot of fertilizer. Outdoors, fish emulsion works well but is not such a good idea indoors. A small dose of miracle grow from time to time couldn't hurt. Too much plant fertilizer will encourage lush growth at the expense of flavor. Once a month is all an indoor oregano plant should need so long as the soil is otherwise fertile.
The container you use should have good drainage, what good would well drained soil be if the excess water can't escape from the bottom of the pot ? The soil should be allowed to dry out in between watering.
Oregano grown in pots does not stand up to cold weather all that well so temperatures should be maintained at 65 -70 F and 55-60 F at night.
Oregano does best in full sun, a minimum of 6 - 8 hours daily even more. It should be placed in a sun drenched location or provided with sufficient artificial light if at all possible.