How I did it: Took a bag with a little rug, pens and notebook to the little park round the corner. Looked suspiciously at the grass then laid the blanket out. Drew a little picture of a baby hitting its comatose mother over the head with a rattle while a small dog sat beside them. Wrote down what people said as they went past. E.g. "You can have cream and ice cream with it if you want to."
Lessons & tips: Start small.
Resources: Paperchase notebook.