What HTML Tags Are Significant to Search Engines

I know that obviously crawlers and spiders index sites based on their meta, H1, H2, alt, title, and all the basic ones. But do search engines prefer sites with proper tags for site's. So for instance, lets say I don't use the tag but only for my navigation bar? Or maybe if my classes are named randomly? Is there more to a sites source code that search engines look for?P.S.- This is my first time posting on BHW, its been 6 months since I signed up for BHW. And I've been on here nearly everyday just learning, before I made my initial start to IM. So far it has been a fun time, and I will soon post a thread of my journey.

Search for the main pages in your niche. Open them up and see how they do it. Do they have h1? Do they have meta tags? Do as they do.

Welcome to BHW. Looking forward to your journey thread.