I also learned a lot from RR, and I learned a lot of my mixing from a great video that John Merchant did several years ago. He provided the raw tracks and walked through the mixing process using mostly stock plugins and entirely in the box. It allowed me to do it along side and see and hear what was happening.
Mike Senior’s book “Mixing Secrets” was quite valuable. As well as the music library that he hosts.
Those are what quickly come to mind.
I catch neat little tricks on forums and videos all the time, but for me really it comes down to practicing and actually doing it. Start projects and finish projects, and move on to new projects. Try a few new tips on each one