It's important look at the histogram on the LCD display when shooting photographs with your digital camera. This is especially true when you are shooting in a contrasty lighting situation like the one illustrated by the attached image. There are dark values in the clouds and mountains, and brilliant highlights in the snow-capped mountains.
Using the program settings like shutter priority or aperture priority, the camera tends to underexpose because it sees so many bright values in the sky, which is taking up two-thirds of the image.
What to do? Use the exposure compensation function, and open up the exposure until the highlight values come close to, but do not touch the right edge of the histogram. Now both the dark areas and the highlights have detail in them. Here's the histogram once that adjustment was made.
For more information on this, and other photography tips, check out my blog at ABetterPhotograph.com.