I recommend reading some academic journal articles about deception detection rather than online magazine articles and so. Many of the often-quoted ways to detect deception have been empirically shown to provide no statistical advantage in telling whether people are lying or not.
You want to establish a baseline before being able to assess if people are telling the truth. If people suddenly deviate from that baseline, verbally or through their body language, it is usually an indication that the subject is bringing up some kind of feeling in them - it is then up to you to interpret whether this is a sign of deception.
I read a very interesting article where test subjects were asked to determine if a person was lying when telling a story. The answers showed no statistical significance one way or the other, so in this test, you may as well have flipped a coin. However, when they were asked to determine whether a person was thinking hard when telling a story (based on the assumption that people think hard when they lie), the subjects were able to much more accurately tell if a person was lying.
TL;DR: Detecting deception is not easy and can never be covered by popular statements like "If a person breaks eye contact, they are lying".
