1. When the moon is full, follow the Sunny 16 rule. Because a full moon on a clear night reflects sunlight just like the earth on a clear day, avoid getting an overexposed ball or an underexposed foreground by setting your aperture to f/16. Determine your shutter speed using the formula 1/ISO. For example, if you're shooting at ISO 200, the shutter speed should be 1/200 sec.
2.** In other phases, open up the aperture. As the moon waxes and wanes, its brightness stays the same, but there is less light overall, so adjust by 2.5 stops in the first or third phases, and 10 or more stops when it has a thin crescent shape to get a good foreground exposure.