Sleep? If you can't get lots of it in one go, maybe lots of short knaps..?
Think before people come out with suggestions like slices of cucumber on the eyes or cold tea bags etc, I'd like to know what causes it and the biology behind it.
Maybe it's down to dehydration? Drink lots of water....?
"Bags under eyes — mild swelling or puffiness under the eyes — are common as you age. With aging, the tissues around your eyes, including some of the muscles supporting your eyelids, weaken. Normal fat that helps support the eyes can then move into the lower eyelids, causing the lids to appear puffy."
Not cheap @ £40 (lol) but Brickell Men's Eye Balm is the only one which worked for me. Though each tub lasts for ages as you only need to apply a very very small amount under each eye. Not kidding, but i had eye bags almost like Alpha's from The Walking Dead