Here is another tip I learned From Gloria Kempton's book Dialogue
If you open a scene with dialogue, integrate some setting details as quickly as you can so the reader can begin to picture the characters and the atmosphere in which the dialogue takes place. This is one way to make the scene three-dimensional so your characters aren't talking to each other in a vacuum.
This book has once again proved it's value to me. I consult my book whenever a scene full of dialogue feels like it needs a jump start.