You may find some of these psychological hacks as funny, weird or even plain wicked (see #16); but all of them are pretty useful to improve your people skills. Try these and see how it works for you!

1. First Impression - When you first meet people, try to notice their eye color while also smiling at them. It might be because you look for a second or two longer, but I can tell you that people really respond to it.

2. Control the Frame - When people are angry at you, stay calm and it’ll get them even angrier. When someone insults you, either ignore or mock them. Never lose temper. They’ll be ashamed about it after.

3. Turn your Torso - As you are listening to someone, you can make them feel valued by keeping your toes and torso pointed at them as they speak. It’s kind of like nonverbally telling them that you are interested in what they have to say. And that is the best compliment you can give someone.

4. Use a Triple Nod - When someone finishes their statement, look them in the eye and nod three times as if to say, “keep going.” They often will continue and you end up having a much deeper conversation. (And if they don’t it’s no big deal, just take a sip of your drink and ask your next question).

5. Silent Treatment - Nothing is worse than a silent listener. People will go to any extent to break your silence and while talking or negotiating and sometimes they even give up their key point just to make you interested. If you ask someone a question and they only partially answer just wait. If you stay silent and keep eye contact, they will usually continue talking.

6. Parental Wisdom: If you want people to take your words more seriously just say, "This was what my father/mother taught me when I was a kid". People tend to believe in parental advises.

7. False Attribution of Arousal - When you take somebody out on a first date, take them somewhere exciting that will get their heart beating such as a roller coaster or horror film. This gets their adrenaline up. It makes them think they enjoy spending time with you rather than the activity.

8. Remember their Name - Refer to people you’ve just met by their name. People loving being referred to by their name and it will establish a sense of trust and friendship right away.

9. Add some Embarrassment - When you are lying to someone right to their face and don't want to get caught, just add some embarrassing detail to it. People tend to believe those lies because no one likes to share embarrassing details unless they are true.

10. Story first, then Data - Although data is always accurate, people tend to believe in stories and overlook data. So when you are giving someone some data, give it with a story first.

11. Social Joke breaker: If someone is cracking a joke about you or your friend in a group, just pretend that you can't hear them and ask them to repeat. Then stop them in between for answering a text or something, apologize and ask them to repeat again, no joke is funny for the third time and no one in the group laughs.

12. Rock Paper Scissors: Do you want to win a Rock Paper Scissors game? Just ask the opponent some (any) question! Their brain automatically goes into defense mode to prep to answer question and almost always people defensively throw Scissors.

13. Detect your Stalker: Ever get the feeling that someone is watching you, but you're not sure? Try yawning and then glancing at your suspected stalker. If they yawn, then you know they've been watching you, since yawning is contagious or look at your watch. If they are indeed watching you they will usually look at their own watch.

14. Exposure Effect - People tend to like you more just because you show up in front of them often. If you like a girl and want her to likes you back, just keep showing up. But provided she does not hate you in the first place, otherwise she is going to hate you more. And do this trick as natural as you can so that it doesn’t appear too obvious.

15. Annoy your Haters – Got haters? Be an annoying person if you want to get some work done from them. Keep reminding them at regular intervals and they will get the work done to get rid of you. 

16. Sneaky Pal - If you want your friend to carry something (like a bag), just keep talking to them while handing them the bag. Most people will automatically take the bag without thinking.

17. Benjamin Franklin Method - If you ask someone to do you a small favor, cognitive dissonance will make them believe that because they did that favor, they must like you.

18. Find the Leader - Want to find out which people are close to each other within a group and who is perceived as the leader? Pay attention to who is looking at each other when everyone in the group laughs at a joke. People instinctively look at and agree with the person they feel closest to within the group.

19. Effective Persuasion - If you want to be persuasive, try and reduce the use of the words “I think” and “I believe.” Obviously these words do not evoke confidence and the other person will most probably not take you seriously.

20. Confrontation Complication - Whenever you have an argument with someone, move next to them and not in front of them. You won’t appear much of a threat, and they will eventually calm down. This also works well when you are going to be confronted or ratted out by someone. Sit beside them and it’ll make them extremely awkward. No one can sit next to a person that they are about to bad mouth.

h/t Quora