When it comes to increasing your keyword ranking, there are three main types of methods you can use: on-page optimisation, off-page optimisation, and technical optimisation.  In order to choose the best method for your site, you need to first understand each of these types of optimisation.
On-page optimisation is the process of making your site's pages more friendly to search engines. This includes adding keywords to your title tags, meta descriptions, and header tags, as well as ensuring that your site's content is high-quality and relevant to your target audience.
Off-page optimisation is the process of improving your site's ranking through external means. This includes developing strong links back to your site from other high-quality sites, as well as promoting your site through social media and other online channels.
Technical optimisation is the process of ensuring that your website is as robust as possible.  This includes eliminating errors from spider traps, server issues, dead links, poor mobile experience and poor page experience (speeding-up large slow loading pages which users hate).
A combination of all these elements applied systematically over-time will improve your appeal to users and will likely see a corresponding increase in your organic search engine rankings.