I think everyone here has already heard the term SEO in different times online. SEO basically means Search Engine Optimization but this is wider than what it means. Marketers have a different opinion in terms of SEO but the fact is to gain better performance in search engine like; Google, Bing etc.
Performing the task of SEO is most important here. You have to have a perfect SEO plan based on your niche and you should answer the main question and that is what do you really want to achieve by running the campaign of SEO.
Once you have a clear idea about your plan and goal, then you can move forward to building your content that must meet the need if your targeted audience. Search engine like Goole takes more than 200 factors into their consideration while ranking any site and if you are performing SEO you have taken these factors into consideration too. You have to optimize your SEO campaign both on and off-site. On-site SEO means doing everything that is needed to build a strong content within your site and off-site SEO means to perform you SEO task outside of your website like promoting content by link building and so.
SEO can't be described with a few words but you will gradually develop the task and process of SEO with start doing it. Take your time and give efforts.