Individual level: Careers
I love coaching, and much of my work is summarized in the 2020 FT series, especially how to guide teams, the 'knight's move', and resets.
Larger level: Scenarios
Scenarios are ideal for larger scale guides. How they work is well summarized in a colleague's kind comments:
Largest level: Lessons from history
For the hardest problems, especially when there's no time for scenarios or other explicit processes, it's tempting to just be guided by what seems most relevant from the past. But that's easy to get wrong. Aristotle said that common people like maxims, as it's easy to find one for whatever course of action you want. Businesses - and political parties - do that all the time.
One good way I've found to get around that is to delve into relevant events from the past with enough detail that the true subtleties of what's needed can't get lost. This is what I’ve tried in my Art of Fairness: there's the account of how a remarkable manager organized the Empire State Building construction so it was finished in a bare 13 months; how the Nazi Propaganda Minister Joseph Goebbels used new communication technologies to bring out a nation's worst impulses...and what had to be done to stop that; other chapters have more.
Another way to have a better chance of using history well is to really understand the systematic biases in your sources. I've found that especially useful when helping banking and also telecom groups with their forecasts. These sorts of biases have long fascinated me, and one of my old Oxford lectures has a more general take on how some historians get this wrong, and others more often get it right.