Most orchids originate from a tropical climate, meaning good air, plenty of light, and 12-hour days (365 days a year). The temperature (depending on the species of orchid) should range between 65 to 75 degrees Fahrenheit (18.3 to 23.8 degrees Celsius). Dropping the temperature of the orchid’s environment at night by about 10 degrees will promote new buds, especially during the fall and winter. Many orchids enjoy indirect sunlight: direct sunlight cases them to burn, while not enough creates a plant that doesn't flower. Place your orchid near a south or east facing window. A west facing window may provide too much sunlight and a north facing window may not provide enough.  Check your orchid's leaves if you want to diagnose whether it's getting too much light or not enough. Orchid leaves should be a light green with yellowish tones. If the leaves are dark green, it means that the orchid isn't getting enough light. If the leaves are yellow, brown, or reddish, it means they're getting too much.  Low-light orchids ( Paphiopedilum, Phalaenopsis, and Oncidium) do best if they get northerly or easterly light. Moderate to high-light orchids (Cattleya, Dendrobium, and Vanda) prefer getting westerly or southerly light. Orchids love being behind curtains or window blinds. This way, they get plenty of light, but the light that they do get is indirect. It's easier to kill an orchid by watering it too frequently than by not watering enough. Water your orchid about once per week and allow it to dry out between waterings. During the summer months, longer days and more heat might necessitate a shorter watering period. Water your orchid for 15 seconds and then place it on a tray of pebbles to allow it to dry out. Orchids require much more attention than your average plant or flower. The thicker your leaves are, the more likely your plant requires a larger dose of water. If your plant has bulky faux-bulbs, less water is better. Orchids are not resilient in most occasions, but are when it comes to their water intake. Again, they...

TL;DR in Vietnamese:
Tạo nhiệt độ thuận lợi cho lan. Đảm bảo cây lan phải nhận được đủ ánh sáng mặt trời nhưng không quá nhiều. Tưới cây mỗi tuần một lần. Chăm sóc lan cẩn thận. Sử dụng phân bón dành riêng cho lan, và không bón phân quá nhiều. Duy trì độ ẩm cao. Hiểu rằng mỗi loài lan một khác.