Tamsin: A checklist is a way of developing a disciplined way of selecting moves by applying a list of concepts, priorities or heuristics. For example, I have used a list like this:
1) Urgent: what plays do I have to make or else?
2) Thickness: how can I make weak positions strong?
3) Big moves: what are the biggest moves in this position?
4) Have I missed anything obvious tactically?
I used to use a string of beads, like a mini-rosary, to help me to apply lists like these. I don't know whether they help, but I guess they could be useful for players who are prone to making impulsive moves, because lists make you think about things.
This idea could be expanded into a virtual program for playing moves, so that it is not really you choosing the moves but the list itself. This could be a way of finding out what ideas to encode in a real go-playing program. Please see Tamsin's Paper Go Computer.
Related link: 4 Questions for everyone - Strategy for Beginners