"The first principle is that you must not fool yourself — and you are the easiest person to fool. So you have to be very careful about that. After you've not fooled yourself, it's easy not to fool other scientists. You just have to be honest in a conventional way after that."
Richard Feynman, one of my heroes when I used to study physics. And this idea is valid not only for physics.
P. S. There are several videos of Feynman on YouTube. When I was a student, such a thing didn't exist:
https://youtu.be/ZbFM3rn4ldo?si=-W0A8UhhFqMEIfSa
And Caltech made his Lectures on Physics available online:
https://www.feynmanlectures.caltech.edu/
Bonus: the first chapters of each volume don't need advanced math to understand.