Dialogue is one of the most difficult things to write. I want you to try this prompt and see how it goes. Write a scene where one person wants to leave a place and the other wants to stay. Create a back story for each character that will help motivate them to take action.
For example your characters can be two people in a grocery store. One character is a woman who is having a fight with her roommate and home is the last place she wants to go. The other person can be a store clerk who is anxious to meet a hot date for the first time.
Give them actions with their dialogue and she what unfolds. Remember actions speaks volumes.