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.
Actively identify, discuss, clarify and prioritize a number of actions Source:
Suzanne Garcia via Malte Foegen
Everyone writes one card with an action that they think is important to do - the more specific (SMART), the better. Then team members go around and chat about the cards like in a cocktail party. Every chat pair discusses the actions on their two cards. Stop the chatting after 1 minute. Each chat pair splits 5 points between the two cards. More points go to the more important action. Organize 3 to 5 rounds of chats (depending on group size). At the end everyone adds up the points on their card. In the end the cards are ranked by points and the team decides how much can be done in the next iteration, pulling from the top.
Addendum: In many settings you might want to randomly switch the cards in the beginning and between discussions. In this way, neither of the point splitting parties has a stake in which of the cards gets more points. This is an idea by Dr. Sivasailam “Thiagi” Thiagarajan via Paul Tevis
Prepare 3 flip chart papers titled 'Helped', 'Hindered', and 'Hypothesis' (suggestions for things to try out). Ask participants to help you grow and improve as a facilitator by writing you sticky notes and signing their initials so that you may ask questions later.