To ensure that your indoor orchids receive enough light, place your pots in either a west- or east-facing room or in a room with a bright light. However, do not sit them where they will receive direct sunlight for most of the day (some direct sunlight in the morning will not hurt). However, you can also replicate the right light by using fluorescent or other growing lights, and many orchid-appropriate lights are sold at nurseries and greenhouses. Ensuring the right amount of light ensures that your orchids will not only grow but also bloom.
Many people overwater their orchids, leading to the destruction of the roots and the eventual death of the plant. Therefore, it is essential that you only water your indoor orchids when the soil feels almost completely dry. Furthermore, you should ensure that the potting soil you use allows for the roots to dry off thoroughly, as orchids will die if their roots remain wet all the time. Although most orchids can do quite well with the nutrients from their potting mix, they will really flourish if you also use one of the commercial orchid fertilizers available, such as the Michigan State University formula.
Since orchids are native to tropical regions, they grow and bloom best in high temperatures, and you should keep the air at least 60 degrees at all times, and you should ensure even higher temperatures during the daylight hours. In addition to ensuring regular air flow (stagnant air encourages disease), also ensure that the humidity in your orchid room remains high, as orchids typically grow in climates where the humidity hovers around 50 percent (and sometimes even reaches the dew point). You can also place your pots on wet gravel, or spray the leaves with a mister to ensure high moisture levels.
Not all orchids are equally suited to indoor cultivation. In general, you should avoid orchids that typically grow in very warm or very cool climates, since their accustomed temperatures are not as easily replicated indoors. For instance, cool-climate orchids require temperatures in the 50s at night and not above the 70s in the daytime, which are not easily or comfortably reproduced in most people's homes. You should, therefore, choose a variety that adapts well to the 65 to 80 degree range common to most homes, such as Class IV orchids, which include many intergeneric hybrids.