As we have already seen, light meters cannot see color. They render every scene as 18% middle gray and adapt the exposure accordingly. This will be OK for the majority of scenes, it is only when very dark or bright parts dominate a scene that the meter will be fooled by trying to render it as middle gray.
Most digicams will allow you to compensate the exposure by 1 to 2 EV plus or minus in 1/3 or 1/2 stop increments.
Typically white overcast skies, snow or beach scenes will need compensating by +1 to +2 stops (EV) as the (overoptimistic) meter reading will lead to underexposure.
The opposite holds true for dominating dark scenes like dark foliage or the proverbial black cat in a dark alley. The meter will overexpose in trying to render the dark scene as middle gray, so you should decrease the exposure by -1 to -2 stops. As a rule you should use + exposure compensation when the subject is bright and - when it is dark.
Since correct exposure is only “correct” in the eye of the photographer, EV compensation can also be used as a creative tool. If for instance you feel the mood of an image is enhanced by darkening a stormy sky with –1/2 EV or creating a high key portrait by compensating with +1/2 EV please do so. Remember that the best way to learn what exposure compensation can do is to experiment and try out different settings.