Dialogue is essential to making a story seem real. When was the last time you went hours without talking to the other people in the room. We are social creatures so we are always talking. Small talk mostly but if you wrote small talk that would get boring. Leave out the hi, hello part of the conversation. We know how that works so don't repeat it.
In this task you are going to use dialogue to start a story. Have two people talking. Have the first character ask a question. Any question. Don't worry about what they are doing, just write the dialogue.
Then add in another character and another after that. Have them talking for awhile. Then go back and see if each of your characters have spoken the same amount. Did you forget anyone?
Go back and take out any dialogue that is small talk and doesn't tell you about what is happening. You can add in the others if you accidentally dropped them from the conversation.
Another Dialogue task
Instead of introducing a setting through description try doing it through dialogue. I recently wrote a short story set in a market place. When I described it was clunky and didn't flow. So I wrote in two traders in the market place. I thought of those two from Asterix, the smith and the fish seller. While they argued the environment just developed around them naturally.
So write a scene and instead of going into paragraphs of description have the characters describe it through their words and their actions.