There is only one way to solve your problem: force yourself to get in touch with others and spend more time with others. At first you will feel uncomfortable and nervous, but after a long time, you will become more uncomfortable and nervous, and your immunity will be generated, and the problem will be solved naturally.
As for this question, there is nothing to say. Only by reading more books, reading more newspapers, knowing more about current events and extensively dabbling in various fields can we accumulate conversation materials in our brains and use them freely.