1. You really ought to have not told her that I was leaving.
2. You should know better than to rig he your PIN on your credit card.
Usually, in a conclusion, you wrap up what you have been writing about the whole time. So, a conclusion is basically a summary of the whole text. You can introduce new ideas for the reader, but it is usually inadvisable. In a couple of sentences, you should finish your text, referring to the previous paragraphs and just wrap it all up nicely.
Can you show me some pictures of the story?