When the sun goes to sleep it can light up the clouds. The exposure value difference between the sky and the land increases dramatically and quickly. What I mean is that the sky can still be bright but the land turns dark. This often necessitates a longer shutter speed to get enough light to get detail visible on land. On the flip side of things, this overexposes the clouds in such scenes. This is a problem not only from an exposure point of view but also saps saturation/color. In fact, it just ruins the sky.

          So we face a trade-off. Either we have a nice sky with a dark land or the reverse. Graduated neutral density filters are not always the answer unless the horizon is reasonably flat. The brightest part of the sky in this image is rather low down and close to the rocky mount. There is no way a filter can darken that part of the sky without also darkening the mount, which never looks natural or pleasing.

The best solution is to shoot two images and blend them later. It is really important to expose the sky properly. But what is a proper exposure for a sky such as this? I prefer to under-expose such scenes a bit, yes deliberately. It boosts the color and when I set the white point it pumps the contrast making the clouds pop and stand out from the background.

          Even with a nice sky, still, pay attention to the composition of the land. I am using the footpath to lead to the brightest part of the sky. One is always tempted to boost the darks when blending multiple exposures. Don't fall into that trap. The sun is gone, so the foreground should stay darkish. For an image like this two exposures is typically enough. Now, you might look at this image and say, "the dynamic range in this image is not a problem for one image to handle, why blend two exposures." When someone says that your blending is believable. You have done a good job. The idea is never to create something that looks impossible (at least not for my style of landscape photography). If you are new to photography (welcome), please bear in mind that this scene in reality did not look like this to the camera (the human eye sees this scene as it is shown here but not the camera). Given how the sky looks in this image, reality would have had the foreground much darker. Or looking at the foreground, reality would have had the sky much brighter. It is the blending that makes it look as if it is one exposure. That is what we want to achieve.

          The next time you face a scene such as this. Try shooting two exposures and leave the sky's exposure just a little under-exposed.