What are some SEO hacks that worked for you?

Hi All, I am a complete novice at SEO (have multiple years of Product experience at Amazon). Trying to teach myself SEO so that we can drive organic traffic. Hoping to curate some SEO hacks that have worked for you, tools you have used that have helped in SEO, and lastly even something as basic as how do we learn more about SEO - there is so much content out there but not one single source of truth. For me personally, I have tried the below: 1. Using Fiverr to hire SEO experts to build backlinks. It's at least customer reviewed so hoping it drives some improvement and is relatively affordable. 2. I downloaded Scrapebox. I use the keywords to find the top blogs and then go in and manually comment and share more information about my start-up. I'm still exploring and learning how else to use it as it has many more features. 3. Hiring someone to do an on-site analysis of how to improve the site for SEO. I know my site has latency issues so will be working on sorting that out. Thanks, Ankit