Practice. It sounds stupid, but look in a mirror and try to hold a conversation with yourself. Write down random subjects on pieces of paper, randomly pick one, and try to figure out how to make a conversation out of it.
That's basically what I used to do. It teaches yourself what other people might be looking for in an organic conversation while teaching you where you are stumbling.
text | timaeusTestified
That's basically what I used to do. It teaches yourself what other people might be looking for in an organic conversation while teaching you where you are stumbling.