Good design isn't the kind of thing that's taught as a core class in most educational systems. However, knowing just a bit about how design works can help you in many jobs. This video gives even beginners the kickstart they need.
The video above isn't a tutorial so much as a video periodic table of design elements. Each element -- such as symmetry, negative space and composition -- are demonstrated by themselves in an isolated way. If you don't have any background in design at all, this video may be a good place to start.