What I learned in those years isn't a list of tactics. It's something simpler and more uncomfortable: almost everything that works takes a long time and repeats. There's no trick that replaces steady presence. And steady presence, done manually, is exactly the thing that breaks first when you also have a business to carry.
I came away with one rule I've never strayed from: proactive, not reactive. Most agencies tick off deliverables — this many posts, this many reports, on schedule. I wanted systems that run in the background and report results, not activity. The difference only shows up months later, but it shows up.