First is check out their physical expression. Is it limited and stiff? Keeping extremities to themselves? This is probably a good indicator that they are lying. The liars usually touch their face, throat and mouth. Also scratching the face is another good indicator. And a biggie is eye contact. They may avoid all possible eye contact with their “victim.”
Step 2 Timing and length of gestures and emotions is my next sign. If the display of emotion seems to be longer than what is normal then suddenly stops that is a good sign.
The gestures/expressions should match the verbal statement, for example when a person says “I love you” they should be smiling not frowning.
Emotions such as happy or surprised should involve the whole face, not just the mouth. The jaws and forehead should also push up.
Step 3 Next is their comfort level. Do they seem defensive? A person who is not lying has no reason to be defensive, so watch that sign. A liar will seem uncomfortable looking at their “victim” so they may turn their head to avoid you. Kind of like the eye contact mentioned above. Watch to see if they place objects between you and them. They will go to any length to avoid you…even if it means an object between you.
Step 4 There are some verbal signs such as speaking more than normal, which includes adding unnecessary details. They do not want pauses in the conversation. They may use words to make your question an answer, like if they are asked “did you cheat on the test?” a liar would say “no I didn’t cheat on the test.” Rather than just “no, I didn’t do it.” They may also leave out pronouns or speak in a monotone voice.
Step 5 If you want to test to see if someone is lying, then change the subject quickly. If the person you are testing seems to become more relaxed then that’s a pretty good sign they are lying. The guilty person wants the subject changed, while an innocent person would be confused and will go right back to the previous conversation.
Step 6 finally you can go to https://www.blifaloo.com/info/lies_eyes.php to learn about eye movements of an innocent person and a liar.