If you are thinking about something be sure you are clear about what you are thinking about and why. Ensure you are asking yourself specific questions rather than vague ones.
If you are trying to understand an argument (written or verbal) be sure you understand the exact point at issue.
When engaged in arguments with other people: (a) listen tolerantly and patiently to other people’s opinions, (b) stick to the point, (c) keep calm and cool, (d) avoid personalities, (e) get to the root of the argument.
Arguments which are logically valid, ie. deductive arguments, tell us nothing new about the world, they merely rephrase things we already know. The conclusions are only true if the premises are true.
Just because an argument is invalid does not mean the conclusion is false, it merely means it is not proven by the argument.
For an argument to be valid or reasonable, the following is necessary (but not sufficient): (a) terms must be used consistently throughout the argument, (b) terms must mean the same thing to the different people involved in the argument, (c) the assumptions and external conditions must be the same and consistent in all parts of the argument.
Potential areas of misunderstanding with respect to use of words include: (a) mistaken use of word, (b) different interpretations of an ambiguous word, (c) different interpretations of the scope of a word (eg. are extremes included?), (d) different associations with the word (which may be positive or negative).
Words translated seemingly literally from one language to another often have different underlying interpretations or meanings.
A common shortfall in everyday thinking is taking a possible solution/reason as the only possible solution/reason. This occurs when: (a) we find a plausible solution and assume it is the right one, (b) we preconceive the solution without even recognising the possibility it might be something else.
Left to their own devices, people usually act on the basis of prejudice rather than logic. What people usually think of as being logical is in reality rationalisation of something about which they’ve already made up their minds.
Everybody is an expert after the event. How many argued so coherently about what must happen before the event?
Disagreements generally have at their heart: (a) different interpretations of key words, (b) different understandings of what are valid argument structures, (c) different agreements on the truth of premises.
You can never prove anything by analogy.
Simplifications and generalisations are often very useful. However they have ‘limits’ and these must be understood, and the simplifications/generalisations not used outside of these limits.