Ask HN: What would be your best SEO optimization tip?

Hello HN! I am currently trying to improve the SEO and visibility of my https://get.mymfa.io website but it is particularly hard to find a proper "guide" to get websites to the top of search results and sometimes I even end up reading contradictory information. What would be the most important personal (and non-obvious) tip you would share if you wanted to get your new side project to reach the top search results? Thanks a lot in advance for your help! Jonathan