I purchased a small spray bottle and filled it with distilled water, and I also picked up a couple of optical grade microfiber cloths. The whole kit by the time it was all said and done cost around $5.00.
I start with a quick spray of water onto a folded microfiber cloth, clean the display, and then buff it dry with the other side of the cloth in a circular motion starting at the top left moving across to the right edge and then working down to the bottom of the display, then I also clean around the edge of the display for good measure.
When I clean my computer I usually have the display tilted all the way back, allowing me to also clean the display hinge where dust tends to accumulate over time. It gets cleaned a couple times a month, as needed.
The result? A MacBook Pro that still looks brand new.