If an orchid has bloomed once, that means age isn't the cause of a lack of subsequent buds and blossoms. Orchids have a reputation for being difficult to grow, but that typically is because most growers can't or don't provide the proper conditions. If an orchid hasn't re-bloomed, the cause is most likely something even a novice grower can remedy. Of course, it's possible the orchid has died or is going to die, in which case, toss it out and get a new one.
Insufficient light is one of the most common reasons for failure to bloom or re-bloom, according to the American Orchid Society. Orchids need bright, indirect light to bloom. The best way to determine if your orchid is getting sufficient light is to inspect the foliage. Orchids with deep-green foliage aren't getting the light they need. The American Orchid Society advises orchid growers that a healthy orchid has light, grass-green foliage if it's positioned in the appropriate place and light.
Orchids need a difference in temperature between day and night. If they aren't getting it, they may not produce buds. The average temperature for most orchids is 26.7 to 29.4 degrees Celsius during the day and 60 to 65 degrees Fahrenheit at night. If the temperature consistent in the orchid's current location, consider moving it. And don't guess the temperature; use a thermometer and do your best to provide the proper conditions.
The Wrong Orchid
If your orchid won't bloom, It's possible that you've chosen an orchid that's inappropriate for your conditions. Not all orchids are suitable for houseplant culture and require greenhouse-like conditions. Beginners should stick to Cattleyas or Phaelenopsis orchids, which tolerate indoor conditions well and are a nice introduction to orchid culture. Also, take a second to consider the source of the orchid. It's best to buy from reputable growers who can provide information on the plants. Contact a nearby orchid society and ask some questions.
The Wrong Conditions
Orchids have earned a reputation for being difficult to grow, but that's usually because most growers can't or don't provide the conditions they need. Follow the orchid's requirements to the letter. Skimping, slacking or failing to take the steps necessary to satisfy the orchid's needs will kill the plant. Provide the light, potting media, humidity, watering and fertiliser that your particular orchid needs.