I kind of have a timer in my head. Or a sense of restlessness after a while - a sense that "this is taking too long for what it's worth". When that timer/alarm/restlessness/whatever triggers, I know it's time to try another approach. If it's a meeting, it's time to try to get everyone back on track. If it's a problem I'm trying to solve, it's time to question my approach or ask for help.

No, I can't tell you how I developed this. I had it at least by the time I was in university. (It came in really handy during tests - it kept me from wasting too much time on a wrong approach to a problem.) So, unfortunately, I can't give you any actionable advice. (Unless you get that feeling also, in which case the advice is, when it triggers, don't ignore it.)