During dating you should feel relaxed and be yourself. Just let it flow. The problem is that often we get stuck. We run out of things to say or cannot think of what to do. This could create a mild state of panic, and lead to a downward spiral. It is therefore best to come prepared with talking points, places to go, or activities to do.
If you are extra shy or find communication difficult, you should invest the time to work out how you will explain key things. Otherwise, you may get tongue-tied and become anxious. Better to have a list of questions or topics in your pocket in case you need than risk finding yourself staring at your date realizing you have no clue.