Dialogue is simply a conversation between two people. In order to write a dialogue, you will want to select the characters that will be conversing as well as the topic they will be discussing. There are several different types of conflict in literature. You might want to start with what type of conflict your characters will be discussing. If one character is struggling with an internal conflict, he/she might discuss that conflict with someone else. Since internal conflicts are often emotional rather than physical, it might be easier to create an dialogue involving an external conflict. Perhaps the characters could be arguing or otherwise locked in conflict together. Think of a time when you were involved in a conflict or saw others involved in a conflict. If you start with your personal experience, the dialogue will be easier to write and the conflict will be easily identified.