There are several factors that might be preventing your orchid from blooming. The foremost reason is light. Most orchid generally needs about 5-6 hours of light at the least to bloom. Moving your plants to a brighter spot can solve the problem. Another issue is temperature as some orchids require temperatures to drop considerably for them to bloom while some others require a day-night differential of about 5-10 degrees Celsius to bloom. High Nitrogen fertilizer will also prevent your plant from blooming and this is proven by lush growth and healthy-looking plants that fail to bloom. This can be set right by shifting to a high Potassium fertilizer with an added Magnesium supplement. Another reason could be that you got yourself a seedling and it isn't mature enough to bloom.