Set up a 'retrospective mailbox' at the beginning of the iteration. Whenever something significant happens or someone has an idea for improvement, they write it down and 'post' it. (Alternatively the 'mailbox' can be a visible place. This can spark discussion during the iteration.) Go through the notes and discuss them. A mailbox is great for long iterations and forgetful teams.
'Imagine you could time travel to the end of the next iteration (or release). You learn that it was the best, most productive iteration yet! How do your future selves describe it? What do you see and hear?' Give the team a little time to imagine this state and jot down some keywords to aid their memory. Then let everyone describe their vision of a perfect iteration. Follow up with 'What changes did we implement that resulted in such a productive and satisfying future?'Write down the answers on index cards to use in the next phase.
Divide a flip chart into boxes headed with 'Start', 'Continue' and 'Stop'. Ask your participants to write concrete proposals for each category - 1 idea per index card. Let them write in silence for a few minutes. Let everyone read out their notes and post them to the appropriate category. Lead a short discussion on what the top 20% beneficial ideas are. Vote on it by distributing dots or X's with a marker, e.g. 1, 2, and 3 dots for each person to distribute. The top 2 or 3 become your action items.
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.