The moon against a dark sky is beautiful in itself, but you may want to try a more creative composition. Think about capturing the moon at the beginning of the supermoon phase, picturing surrounds such as buildings, trees and people in the photo as well. If there are other elements in the frame, evaluative or matrix metering will work best unless you are trying to achieve a silhouette effect. Bracketing your exposure a few stops either side will also be valuable, especially if you are in a hurry and want to ensure that one photo will be usable.