Meter the sky, meter the ground, note how many stops difference there is between the two, and then set your camera on manual at the "ground" exposure and add the appropriate GND (if 2 to 3 stop difference, use the 2 stop GND, if 3 to 4 stop difference, use the 3 stop GND). I do it all on manual, including the initial metering x 2, because I am lazy, and being an old-timer I still think in manual not in auto-exposure compensation.