Collect what team members perceived as good, bad and non-optimal Source:
Put up three sections labeled ‘The Good’, ‘The Bad’ and ‘The Ugly’. Give everyone 5 minutes to note down one or more things per category from the last sprint. One aspect per post-it. When the time is up, have everyone stick their post-its to the appropriate labels. Cluster as you collect, if possible.
Hand out pens and sticky notes. Ask everyone for ideas on how to turn the next iteration / release into a certain desaster - one idea per note. When everyone's finished writing, hang up all stickies and walk through them. Identify and discuss themes. In the next phase turn these negative actions into their opposite.
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.