Meta elements attribute to preparing your site in the background so that search engines can harvest the relevant content tags which should mirror the front end of your website. This is called meta tagging. Meta-tagging is building those attributes such as the title and description of a page on your website, images, keywords (which are less relevant in meta data and more relevant on the front end or what's on your page) and image tags. Meta tags also can tell a search engine which is crawling your site as to which pages should be crawled, the frequency of crawling as well as which pages should not be crawled.
3. External Inbound Links:
External relevant inbound links to your website. This is a very important part of optimization. Ensuring that your site is linked from various verified relevant websites, directories, social media sites, blogs, web rings and search engines. Inbound links can be achieved when another website manually places your website's link on their site. Sites which hold content complimentary to your site's content will generally drive more traffic and improve your rankings.
4. Site Speed:
Ensuring that your site is loading efficiently is also key. There can be a number of issues which relate to slow site load:
Large images, external resources(3rd party API's) , internal applications (poorly written), database application conflicts or corrupt files and of course traffic volume to your site. It's important that your site has the mechanisms in place to ensure there is no impedance to speed.