For inspiration you can read The Great Gatsby by F. Scott Fitzgerald and watch the film with Robert Redford and Mia Farrow. Then, you should definitely visit the site Dinner and a Murder. Have you ever been to a Dinner and a Murder party? They were very popular when I was in university and my roommates and I hosted one once. It's still a favorite memory. You dress in costume and play a part. You have to mix and mingle at the party and try to find out things about the other character until you start to find out who the guilty person may be. It's like acting out an Agatha Christie novel.
Anyway, the Dinner and a Murder site has a dictionary of ideas featuring the 1920's from costumes & music to hair & makeup, links to vintage recipes, dancing and music. You can really go to town with this.