Part of SEO is getting backlinks (links from other sites to your site). Search engines depend upon what others think of your site, and they use those backlinks to determine your popularity and your relevance. You don't usually have control over who links to you, but you can certainly encourage others to do so. You can also simply encourage others to bookmark your posts and let others know about your posts. The more this happens, the more likely it will be that some of those people will also link to you. People are rushed and can easily forget to share your posts, even if they loved it. A subtle reminder can make a huge difference.