Keep a check on cost. good quality does not usually came cheap so be prepared to pay enough to get something decent.
Think of the battery backup because you need to know how long you can listen to the earbuds before they need to recharge.
Earbuds should include control pads or buttons on the ear pieces that you can tap to increase volume, skip a track or take phone calls.
Noise cancellation is important as it can help reduce the drone of aircraft engines or the clickety -clack clerk of a rail way track.