Create a list of learning objectives for the team Source:
Hand out pens and paper. Each participant writes down what they wish their coworkers would learn (as a team - no need to name individual people). When everyone is done, collect all items on a board and count how often each one appears. Pick the top three things as learning objectives, unless the team's discussion leads somewhere else.
If your boss had witnessed the last iteration, what would she want you to change? Source:
Imagine your boss had spent the last iteration - unrecognized - among you. What would she think about your interactions and results? What would she want you to change? This setting encourages the team to see themselves from a different angle.
Let team members appreciate each other and end positively Source:
Agile Retrospectives who took it from 'The Satir Model: Family Therapy and Beyond'
Start by giving a sincere appreciation of one of the participants. It can be anything they contributed: help to the team or you, a solved problem, ...Then invite others and wait for someone to work up the nerve. Close, when no one has talked for a minute.