Look at the stems and leaves of the plant to identify any orange, brown or black marks, which means the plant is slowly burning to death from too much sunlight. The leaves will also often develop a wrinkled appearance and feel dry. This occurs on phalaenopsis orchids that are placed in direct sunlight and will eventually kill them.
Examine the area around the orchid pot to see if leaves have fallen off. Then look at the plant itself to see if any leaves are brown or yellow. While it is normal for one or two older leaves to fall off, if many leaves fall off or if small young leaves fall off, it is a sign the plant is dying from a fungal infection.
Tilt the pot sideways and pull the roots of the orchid out of it. Look closely at the roots to see if they are gray, black or have a slimy residue on them. These are all signs that the orchid is dying from too much water. Sometimes decaying roots also smell like mold or mildew.