Put cucumber slices on them .. it does work.
Mostly though .. get lots of sleep and drink plenty of water .. stay healthy!
Wear a bag with a smilly face on it.
Get plenty of rest at night. Stay hydrated. If that fails talk to your parents about food allergies.
Sometimes the dark circles are genetic and there is nothing you can do short of covering them.
However, do you have allergies and/or sinus problems? Are you getting enough sleep? These things can really affect the area beneath your eyes, especially sinus infections. When I was a kid I had terrible dark circles much of the time due to recurrent sinus infections.