Improving social skills is not just a skill, it's a project 
Start by googling and see what comes up, including YouTube podcasts. Key things, based on my own experience, include:
Advance preparation! Don't just meet up with people and hope for the best. You need to do some homework. General homework means reading quality newspapers and books that are being talked about, listening to Radio 4, and then making a list of topics that interest you and which you think would be of interest to your friends as well.
Also, write about events you have attended and how you feel about these. The key is to have something to talk about which is likely to resonate with people - but to remember that you aim to create a dialogue, i.e. your initial spiel should be fairly brief and open-ended. You want to start a conversation rather than dominate it and bore people.
But you also want to focus on and relate specifically to your friends. Start by thinking back to your last few meetings. What did they talk about, who said what, what topics are potentially of interest to you. Write down your thoughts about each of your friends. Who are they, what are their interests, how are their lives, what makes them tick, et cetera. Next time you meet, ask them about something personal that they talked about previously, especially if it is something positive something they were looking forward to.
And always remember: people LOVE to talk about themselves and their own interests. So give them the opportunity to do so
. On the other hand, others get bored quite easily if they have to listen to an endless, detailed monologue about anything, but particularly something they cannot relate to.
The second important thing to remember: everyone is battling demons that you cannot possibly know about. Your worries and feelings of inadequacy are not unique. EVERYONE is scared of saying or doing the wrong thing. EVERYONE wonders why can't I be self-assured, confident, bright, witty, slim, attractive, sexy, intelligent, the bees knees.......... like A, B and C.
Finally, never be afraid of making a fool of yourself. Just don't. As long as you are being genuine and not selfish or overbearing, you WILL be forgiven
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