Social skills are an extremely important set of skills everyone should learn. There are some social skills that are so essential, you absolutely cannot do without them.
Ability to Remain Calm
It is harder to think clearly when you're agitated or unsettled, therefore, it is extremely important that you learn how to remain calm in all situations. Learning how to calm yourself in volatile situations is an extremely useful social skill that can save you a lot of trouble and avoidable stress-related health issues.
Know How to Build Rapport
Regardless of how introverted you might be, you need to learn how to build rapport with others around you because no man can live as an island, and you will eventually need people. Knowing how to build rapport is not a talent, it is a social skill that can be learnt. The only thing is that, depending on personality type, some people just need to put more effort into it than others.
Know the Difference Between Being Assertive and Aggressive
There really is a thin line between the two, this is why it is so important as a social skill to be aware of the difference between them. It's okay to passionately share your opinion and stand your ground on it, but you need to be aware and ready to check yourself if you find yourself bordering on insulting or offensive. At that point, you have already entered into the zone of aggression.
Learn to Be Flexible and Cooperative
We live in a world with billions of people, and the fact is we won't all have the same opinions or point of view. If you don't want to end up fighting everyone you meet, you need to learn to be flexible and cooperative. You may feel that your way is the best way, but it important to still remain open to the suggestions and contributions of others. Be flexible enough to compromise when you need to, because no matter how intelligent or self-sufficient you are, you will need other people to get ahead in life. You can't do it all by yourself. You should therefore be open to sharing ideas, making necessary compromises and being flexible all together.
Learn How to Communicate
Communication is more or less an art (though there are some that argue it is a science), and the truth is that there are many ways to communicate, you only need to be sensitive to the best means of communication to use in different situations for different people. You should learn when best to communicate face-to-face and when to communicate through written words. You should keep in mind that written words carry little or no emotion, so it really shouldn't be your choice communication channel when communicating emotional or deeply moving subjects.