Collect some news headlines in advance and take them to the retrospective to serve as examples. Try to gather a mixture of headlines: factual, opinion, review. Place the headlines where everyone can see them. Hand out sticky notes. Give team members 10 minutes to come up with their own headlines describing newsworthy aspects of the sprint. Encourage short, punchy headlines. Stick the completed headlines to a whiteboard. If any cover the same news item, combine them. If any are unclear, ask the reporter for details. Vote on which news items to discuss and analyse in more depth.
Asking and answering go around the team circle - an excellent way to reach consensus Source: Agile Retrospectives
Everyone sits in a circle. Begin by stating that you'll go round asking questions to find out what you want to do as a group. You start by asking your neighbor the first question, e.g. 'What is the most important thing we should start in the next iteration?' Your neighbor answers and asks her neighbor a related question. Stop when consensus emerges or the time is up. Go around at least once, so that everybody is heard!
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.