It's easy to make a coloured block of text, or a simple diagram (e.g. a flag), but to make it look like it's actually real, you'll need to follow the steps in this tutorial.
The effect in this photoshop tutorial can be very cool if used creatively either by itself or as part of a larger process. Its also one of the easiest things in the world of Adobe Photoshop to accomplish. Try using it in sbtle ways ona family photograph to give a soft glow to someones skin and give that photograph that little extra touch.
On the web, most things that aren't photographs, are two-dimensional, monotone areas, devoid of lighting.
The key to making websites that really stand out has to do with two factors - lighting and randomness.
This tutorial goes through the steps of making a very funky piece of wallpaper.