Type of headphones: There are three main types of headphones: in-ear, over-ear and on-ear. The type you choose will depend on how comfortable and how you want to use the headphones.
Sound Quality: Sound quality is an important factor to consider. Check that the headphones have good frequency response, impedance and sensitivity.
Ratings and opinions: Search the ratings and opinions of other users to get an idea of the quality and performance of the headphones.