Not sure if it works, but I've read that using anti-inflammatory creams such as Preparation-H can reduce the circles. Some models also use cucumber slices.
My ophthalmologist recently told me to use baby shampoo (e.g. Johnson & Johnson's No Tears) to wash around my eyes on a regular basis. Women spend a lot of time cleaning around their eyes, mostly in their attempts to remove make-up at the end of each day. We, as men, don't need to focus on this, so our pores don't get the same attention, sometimes leading to puffiness and dark circles. I've started a routine of using baby shampoo on my eyes a couple of times a week, and have witnessed a noticeable improvement in appearance.