With Google constantly updating and giving certain metrics and such, then changing....is rhere one SEO technique that has changed very little over time, that still is as good as ever? (not content, more of a technical question)
Not sure its a relevant question to be honest. Google's aim is to satisfy the searcher's intent is fast as possible. Making sure you are the best resource for a specific "search intent" should on paper be the best strategy always. Right now the only reason we talk about "SEO techniques" is because Google is just not smart enough yet and can still be influenced by savvy marketers. As Google gets smarter, we have to adapt. The techniques closest aligned with "search intent" will win long term.
Think just smarter and make older techniques in new ways ... Always try to make natural backilnks . just use your mind my friend ,its only your mind game