For me personally, developing productive Socratic dialogs when whiteboarding is my biggest challenge. I printed three posters to prompt students to contribute effectively to whiteboard discussions and to help them prepare excellent whiteboards. One of these posters ended up in the background of a photo I tweeted and generated a couple of questions. The content of the posters is directly from the article Engaging students in conducting Socratic dialogues: Suggestions for science teachers by Carl Wenning, Thomas Holbrook, and James Stankevitz. (Jim was the leader for the Modeling Instruction workshop that I attended.)
Based on this article I created three posters: Questions to Ask (prompts for questions), Lab Presentation (tips for whiteboarding labs), Whiteboard Presentation (tips for whiteboarding problems).