normally hereditary-watch ur diet,sleep etc.
try natural homemade methods like cucumbers, cool teabags, potato slices etc. no7 eye gel does the job for me but i hardly have dark circles. my mums is permanent have tried nearly everything nothing works for her.drink up plenty of water/juices, have a balanced healthy diet with excercise, aim to get at least 7 hrs sleep.concealers are quick fixes like the ysl/no7 one.