When it comes to Search Engine Optimisation, or SEO, that clichéd phrase "It’s not what you know, it’s who you know" doesn’t really apply. A more appropriate phrase would be: "It’s a little bit of what you know and a little bit of who you know, too".
This is because there are a number of ways that you can improve your sites search engine performance in-house, such as producing original, keyword rich text content. Another important factor in the climb up the search engine rankings is the sites popularity; if you already receive a lot of hits, the search engines will consider you a more valuable source of information. And yet another important factor is the number and the quality of links to your site. If there is a site which has plenty of authority for your search topic (such as McDonalds if your subject is fast food), then you can endeavour to secure a link to your site from that authority site.
Thus, not only will this link carry plenty of rankings boosting authority it is also highly likely to result in plenty of visits to your site via the link. This, in turn, boosts popularity. So the equally clichéd phrase "Killing two birds with one stone" is definitely appropriate.
Study the work of influential bloggers and authority sites within your niche topic and then try to generate original material for your site that might encourage these external agents to link to you. Targeted linkbaiting is a proven technique. Your blogs, images, videos, podcasts could earn you links from these influential web presences, whose followership and popularity exceeds your own, but can benefit you and boost your popularity.
Alternatively, you could simply approach these influential bloggers or larger authoritative sites and request that they reprint your material or invite them to include the link. Either way, the relationship could certainly improve your SEO performance.