SEO (or Search Engine Optimization) are the steps that content creators and web developers/designers take to increase a sites visibility in search engines in response to various search queries.
The goal is to figure out what terms, sayings, or reasons possible users may try to use to find your site. Then you make sure that your site is returned in response to these queries. Simple, right?!
Well obviously there is slightly more to it than that. However, this is a completely learnable skill, that takes a little inspection, and attention to details. After some practice, you will find ways of getting your sites to turn up at the top of relevant searches.
To get going on this;