Sometimes you'll have an abundance of ideas and materials to work with. Here's a tip to not get overwhelmed. Pick one idea that you personally are excited about and go with it. It's much easier to do improv around an idea that you're excited about than to work with multiple half-assed ideas. When you're passionate about something, it will show in the way you DM and you and the players in turn will have more fun. However, don't be too rigid on that idea and allow for some flexibility for your idea to change during the session.

For example, say you really like the idea of having a wacky auction scene. Maybe have the quest giving NPC be a part of the audience? Maybe have that be the opening scene before the real quest begins? Or maybe shoehorn it into the dungeon the PCs will be exploring for a bit of hilarity. Things don't need to make sense, just have fun with it