Easy answer:
If you have a friend who has great social skills and you’re comfortable with them, ask them to teach you how. It’s kind of like learning to fly an airplane. Ask them to gently introduce you into conversations, activities and social situations. Have then “pilot” at first but let go occasionally and let you fly but still be there to save you from any uncomfortable silences or blunders. Then have them wean you off of themselves. A person with great social skills should be able to do this for you, but finding one who’s willing might be a problem.
Hard answer:
But for most of the people on the internet asking “Why can’t I talk to girls?” or “How do I create social skills out of nothing?” the answer is practice, but their question is wrong. It’s not something you can learn and just keep with you for that half an hour on fridays when you run into actual people. For people who feel their case is hopeless it requires a fundamental change of lifestyle - you have to spend your free time with people or you won’t be able to do it well. I don’t mean Saturday lunch with your friends.
You need to spend a lot of time with social people. You don’t specify your sex, gender, age or marital status but that’s largely irrelevant unless you want very specific advice. You want to be living with other people, and if you don’t want to, you probably don’t want to spend too much time at home until you are comfortable with your sociability level. You don’t want to live with busy professionals or business people, perfectionist college students, or people who play a lot of games (more on this later). Ask yourself honestly if you are elitist or prejudiced. If you are, it’s going to be a lot easier if you stop. People drinking themselves stupid in fraternities or working minimum wage retail at the age of 35 are not better or worse than anybody else until you can judge them individually. You can’t do that without socializing with them first.
After my father died when I was 10 years old I started drifting away from my friends, and finally when I changed countries I just locked up and spent a good 7 years being an antisocial dork with at least a 2.5 year period where I did not have a single friend in my area. None. Not a single in-country phone call that I could make during high school. During that period I did not call or write any of my friends back in Russia either, not once. About 2.5 years ago I got sick of it and I took a very aggressive approach. I went from spending most of my time at work and at home to spending at least 40 hours a week doing something with somebody - something social. Now I’m a social dork with other problems, but I’ve achieved my goal. You can too if that’s what you really want.
Ok, you’re on the internet since you’re asking this on SDMB. In general the internet is your enemy. However the internet is also a great resource for meeting people when you have trouble doing so in person or if your social circle simply sucks. However, if you choose this route, look for people in the area and don’t spend too much time talking online. Talk a little (a week or two), meet, move everything offline with that person. Meet their friends, relatives, everybody. Ignore the little voice inside your head “I don’t like that person”, “They’re not my kind of people”, “I hated that type in high school” - it’s not just unhelpful it’s blatantly wrong. You are simply looking for an excuse not to do what is intimidating and you can’t let yourself take it.
Do you drink? If you don’t, fake it. People use alcohol as a future scapegoat for the potential disaster that arises from lowered inhibitions. I’m Russian, I have amazing tolerance for alcohol, and I’m not a small guy. I become much more uninhibited and confident simply holding a drink. Now I don’t need this but at first it was tremendously helpful - it’s a good shield. Again, if you have a friend who can be your shield, use that.
Ok, about the people. So what’s wrong with gamers and games? (This includes video games, most card games, Risk/Diplomacy, chess, etc.) I don’t know, but these people tend to have this problem as well and you’re not going to help each other. You’re just going to trick yourself that you’re being social and fall into a niche of a couple people near an X-Box that keep saying things like “We should go do something”. Basically you want to pick charades, pictionary, and twister over anything that people pay attention to rather than each other.
So what kind of people should you concentrate on? Well, this is largely a matter of taste, but the kind of people that that majority of SDMB would find boring. Smart people who have a lot of free time and like to spend it socially - drinking, throwing parties, playing pictionary, just hanging out if they can’t find anything to do. Childless single people in your age group who have free time and a wild streak. This is a vast generalization but lawyers, doctors, dedicated college students, engineers, mothers, etc. tend to be the types that are hardest to communicate with socially. when they are sober.
If you have a lot of problems with nerves and awkwardness that seems debilitating, talk to a shrink if you can. Having or not having Antisocial Personality Disorder or Aspergers or whatever is completely irrelevant - psychiatry does not treat diseases as much as it treats symptoms. Don’t forget that talking to a shrink if you don’t have one already is a much more social act than asking a message board. I’m not recommending getting anything prescribed or beginning therapy, that’s up to you.
This is probably the most disjointed and poorly written response that I’ve ever posted on SDMB, but I hope at least some part of it is going to be helpful. One key thing to remember, if anything at all:
Just because it seems it comes natural to other people doesn’t mean there is some magic bullet that’s going to make it natural to you. If you want to become good at this, you’re going to have to temporarily change a lot of your life. Most likely if you’re asking this question your lifestyle is not compatible with learning to be social , while it is probably partially compatible with simply being social once you are comfortable with it - this is what’s so confusing. It seems that were you another person events in your everyday life would unfold differently - you’d strike up conversations at your grocery store and make friends waiting at the dentist’s office. Yet, if you were that other person you wouldn’t necessarily be in those places! While it might be excellent to be social within the life you have now, it hasn’t done a good job at teaching you being social now has it? Change it.
You might have to move, change jobs, take a break from some friends (explain, they’ll understand), do potentially dangerous and stupid things, and none of it is going to be easy at first, and some of it is not going to be fun at all. At some point you can re-evaluate your life and change everything anew , possibly back to the way it is now.
Good luck and we’re here to answer questions if you have any.