Cold compress can constrict the blood vessels under the eyes and help a lot in reducing eye puffiness and dark circles.
Soak a washcloth in cold water or cold milk. Put it over your closed eyelids for several minutes.
Alternatively, you can wrap a few ice cubes in a soft napkin and place it under your eyes for a few minutes. You can also use a bag of frozen peas, a chilled teabag or a cold spoon.