Unless you're in a perfectly lit studio environment and spend a lot of time perfecting the shot (light and colour wise), photos can sometimes appear washed out and a little "grey".

There's a very simple little trick that I use to sometimes bring out subjects and really enhance areas of the photo. For example, shadows can sometimes be too blended into the background, tweaking them a little can really add contrast and make the rest of the image much more vibrant.

Here's an an example - an image which I took on a rather bleak day, it's not terrible - but it would be nice to make the ocean appear a little more blue, and get the sand/rocks much more lighter. The trick is to 'tweak' the photo and not ruin it, it is possible to brighten up a photo so much that it looks fake and "overdone".