The most important thing is to tell your true story. They sometimes ask you about special events, dates or things like what you were doing in that one moment. They do that to see if you are really telling the truth about how you came to Germany and that you have a reasonable reason to stay here. You should write down your whole story and every detail that you remember and which you experienced during the way to Germany. Then read your text and remember it.
Good luck and don't forget to tell the truth... sometimes they just see if there are any false details and this can end into a catastrophe.