Expert detectives have two main qualities:

• Detached involvement
• The ability to keep on asking questions

Good investigators don't make quick judgements. They know that their mind will try to convince them that their first impression is right. Instead, they force themselves to walk away from a problem they want to solve. This can help when making important life decisions where it would be dangerous to jump to conclusions, such as buying a new home, hiring a new employee or planning a career move.

• Assume nothing
• Believe nothing
• Challenge and check everything

It is hard to resist our automatic assumptions and our need for closure. Therefore, always ask yourself what you do know and what you don't know. Remind yourself that correlation does not imply causation. To help find the truth, try to disprove your conclusions.

The favoured approach is not deductive logic, which is reasoning based on known facts, but abductive logic, which identifies the best possible explanation in the absence of complete knowledge. Doctors make use of abductive reasoning. They are given a set of symptoms and diagnose on what would best explain most of the symptoms.

Always create a short outline of all the possible alternative explanations you can think of. Then plan how you will test your different reasons.

Use a systematic approach to eliminate as many explanations as possible through falsification.

• Collect the available information.
• Check the facts for accuracy and relevancy.
• Connect the dots. Do different sources say the same?
• Construct all possible solutions.
• Consider what information you need the most to test your remaining hypothesis.
• Consult with somebody you trust to help narrow the scope of your investigation.

When constructing alternative options, you may find that you will gather more possibilities than you perhaps thought of in the beginning. To assist our minds, we need practical methods and information-handling tools to keep track. This will reduce the risk to jump to conclusions.

A mindmap or matrix can help to create transparency and allow for a second opinion of your ideas. With every bit of new information, mark on your matrix what the implications are for each hypothesis.

We will always forget something or not have all the facts. That's why an open-minded and critical friend can be indispensable.

Evidence and new perspectives can be found where you least expect them. It is essential to hold back your own opinion, ask open-ended questions, and use silence and active listening techniques.

Whether you have to work out why a product launch failed, why your kid is struggling at school or why your smartphone has stopped working, it is essential to think more systematically.

But you won't always know everything and perhaps won't ever know. If you learn how to write down your understanding systematically, you'll increase the chance of finding a simple solution and avoid blunders. Practice can help to sharpen your inner detective and improve decision-making.