What are some of the best self-defense strategies/ tools every person should know in case of danger?
I think the first go-to strategies are de-escalation tactics. Ways to build rapport and recognise the verbal/non-verbal signs of aggression building. If one can stop a situation arising, this is better than adapting to the situation once it's erupted where there are fewer options available.
Good communication skills are crucial
Psychology is of immense use.
But if all that fails, retreat is also a very good step.
If all that fails, one can utilise classes in self-defense which will teach one not only how to defend themselves, but how to control one's emotions so they don't get the better of you.