3 ideas
Build a working knowledge of the major models from every important discipline — physics, biology, economics, psychology, math — and hang your experience on this lattice rather than memorizing isolated facts. Most problems require crossing disciplinary boundaries, so a person armed with only one discipline's tools will force every problem into that single distorted frame.
Solve problems backward by asking what would guarantee failure, then systematically avoid those things, rather than only asking how to succeed. Many situations yield their solution more easily when you describe the disaster you want to prevent and work to eliminate its causes.
When several psychological tendencies operate in the same direction simultaneously, their combined force is not additive but multiplicative, producing extreme and often irrational outcomes. Recognizing these convergences explains phenomena like cult recruitment, auction overbidding, and market manias that no single bias could produce alone.