Start by stop talking as much.

Unconfident men talk far too much, and the more you talk the less interesting you will be to others.

Just sit back, listen and if you have nothing interesting, fun, or make a point then go for it. If you don't have a strong opinion on something, don't speak for the sake of it.

Also if women are dramatic about something ég causing a fuss over nothing big, don't join in with the chit chat. Sit back and say something productive, an answer basically something with authority.

I'm working on this myself. There is no other way than to just... be more stoic, like how losing weight is "simply" just eating less.

Anyway, I make an effort to think about how I behave, reflect and be better. For a start, be quiet until you actually have something to say or someone goes up to you. Don't overreact to everything someone says, like you don't need to laugh or say "that's crazy" after every sentence. Make jokes but don't laugh at your own jokes. If you get crickets keep going as if nothing happened. Smile a bit but not too much. Don't move your hands or entire body too much while talking. Talk clearly and not too fast. If someone says something you disapprove of, ignore it. If something bugs you, think about if it's really that big of an issue and only bring it up when it is. If you bring it up, don't argue. Never argue with a woman. If she tries to start shit, walk away bro.

Do you need to have an emotional reaction to emotions or events (which are in fact things that trigger emotions, so in practice event=emotion)?

Should you have an emotional reaction just because you feel an emotion?

Should you display an emotional reaction to feeling that emotions inside just becasue you feel it?

There's nothing wrong in having emotions, there's nothing wrong in having ANY level or amount of emotions, you decide. That being said, emotions aren't supposed to be firing your reactions like a mailman fires a dog, just by mere appearance. Another thing: is displaying emotion abc in context xyz helping me or not?

Chances are you acquired a habit of having emotional reactions to stuff. Emotions themselves have an ability to self-perpetuate, you feel an emotions, it makes you react (move more, talk more), that reaction has physiological feedback resulting in feeling this emotion longer. As with any habit, you strengthen it by repeating it. Same things goes for getting rid of one you don't want.

Best way to start on this is diary, meditation plus being conscious about your behaviour. You notice, you either manage to stop it or you don't, you write it down (pen and paper, not txt file) later as lesson/reminder, perhaps you notice patterns. The more you practice this the more it will become your second nature. Meditation is there to allow you to observe your thoughts and let them go, in real life this translates to having an additional time (and "skill") between the trigger and reacting to it.

Meditation tl/dr: pick spot on a featureless wall and stare at it for half an hour a day. Let your thoughts come, but do not engage in with them. Sounds silly but it works, just be honest with yourself, no dozing off into semi-dream state, no engaging with the thoughts, just observing as they come and go. You can focus (but not too hard) on observing the physiological breathing.

https://www.youtube.com/watch?v=KIjJLdsrz90

No staring into candles, engages mind gives it something to do, not what you want. No guided meditation, that's self-hypnosis and self-indoctrination, you want empty space between trigger and reaction not more thoughts.

Mindfulness meditation is like lifting but for the mind. Every time you catch yourself stuck in a thought loop, you redirect your focus back to the breath. That is the equivalent of a single rep bicep curl.

Meditation even just 10 minutes a day will gradually change your emotional control & increase the time between emotion felt -> external reaction. You will also be very calm in high stress/high pressure situations. Theres a reason the shaolin monks in china can get kicked in the nuts and tank it, or can break bricks, among other insane physical feats.