13 Tips in Thinking and Reasoning

1. Whenever possible, consider alternative hypotheses. As we have seen, we humans are not in the habit of evaluating evidence in dispassionate and objective ways. One of the simplest things we can do to improve our capacity to think and reason is to discipline ourselves to consider alternative hypotheses. Something as simple as merely forcing ourselves to list alternatives can improve the reliability of reasoning.
2. Reframe the question. Is that soap 99.4 percent pure or 0.6 percent toxic? Politicians, advertisers, and even our local supermarket staff routinely spin just about everything we hear, see, and read. Everything is presented to be as positive as possible. Our job—as consumers, voters, and citizens—must be to perpetually cast a skeptical eye and develop a habit of rethinking whatever we are asked.
3. Always remember that correlation does not entail causation.
4. Never forget the size of your sample. From medicine to baseball statistics, people often fail to take into account the amount of data they've used in drawing their conclusions. Any single event may be random, but recurrence of the same pattern over and again is less likely to be an accident. Mathematically speaking, the bigger the sample, the more reliable the estimate.
5. Anticipate your own impulsivity and pre-commit. Odysseus tied himself to a mast to resist the temptations of the Sirens; we would all do well to learn from him. Compare, for example, the groceries we might choose a week in advance, with a well-rested stomach, to the junk we buy in the store when we are hungry.
6. Don't just set goals. Make contingency plans. It's often almost impossible for people to stick to vague goals like "I intend to lose weight" or "I plan to finish this article before the deadline." Gollwitzer shows that by transforming goals into specific contingency plans—of the form "if X, then Y" (for example, "If I see French fries, then I will avoid them")—we can markedly increase the chance of success.
7. Whenever possible, don't make important decisions when you are tired or have other things on your mind.
8. Always weigh benefits against costs.
9. Imagine that your decisions may be spot-checked. Research has shown that people who believe that they will have to justify their answers are less biased than people who don't. When we expect to be held accountable for our decisions, we tend to invest more cognitive effort and make correspondingly more sophisticated decisions, analyzing information in more detail.
10. Distance yourself. Whenever we can, we should ask, How will my future self feel about this decision? It pays to recognize the differences in how we treat the here and now versus the future, and try to use and balance both modes of thinking— immediate and distant—so we won't fall prey to basing choices entirely on what happens to be in our mind in the immediate moment. (A fine corollary: wait awhile. If you still want it tomorrow, it may be important; if the need passes, it probably wasn't.) Empirical research shows that irrationality often dissipates with time, and complex decisions work best if given time to steep.
11. Beware the vivid, the personal, and the anecdotal.
12. Pick your spots. Decisions are psychologically, and even physically, costly, and it would be impossible to delay every decision until we had complete information and time to reflect on every contingency and counteralternative. The strategies I've given in this list are handy, but never forget the tale of Buridan's Ass, the donkey that starved to death while trying to choose between two equally attractive, equally close patches of hay. Reserve your most careful decision making for the choices that matter most.
13. Try to be rational.

Source: Kluge: The Haphazard Construction of the Human Mind (2008) by Gary Marcus.