High Volume SEO Professionals: How to get started doing my own SEO in-house?

I'm curious as a freelancer if SEO is something I can grok and get going with in-house rather than skipping it all together or hiring someone to do it. I'm a quick at learning of a lot of different disciplines and very entrepreneurially minded. I enjoy writing content and engaging with people online. What are some tips for someone like me who wants to pick up the SEO craft? For a while people were saying don't overthink it or try to guess what the search engine is thinking. Is that still valid in 2025? Do I need to consider bots that scrape content for AI? What are the main things I should pick up / read up on / follow?