Here we will mention the factors that must be taken into account within the site, and we will quickly mention them, not in detail:
Content on the site
We must pay attention to the content mainly because it is the basis for all the adjustments that follow, in case you have a strong foundation then the first places are yours. (See the importance of content in raising the ranking)
Links should be well written and split. This is an example of good links:
http://www.dmoz.org/Games/Video_Games/History/
Image titles
It is important in the process of website optimization for search engines that you give titles to the images that you share on your site pages because these engines like to know more in detail the identity and type of images that you archive.
These were the four most important factors that you should focus on improving in case you want to achieve better results for your site. There is definitely more, for example, the distribution of tags H1 - H2, which we may mention later.