I prepped up covered MDF boards in simple areas of coloured vinyl to vaguely depict sky, water, town, park etc. The children then had the freedom to cut the shapes they wanted to directly from the sticky vinyl. I didn't direct them much at all. There was a distinct gender bias - the boys naturally worked together and produced images of rockets and robots and things with wings! whilst the girls made images like butterflies, ladybirds and birds. All the children got absorbed into what they were making and found cutting the plastic very easy as they had had stickers from an early age. I loved the results!
Here is what they produced for sessions. The feedback was that the students loved doing it, were wholly engaged and the staff were very pleased with the results, especially with the engagement of everyone and that the murals can be used outside, so had long term effect too.
It was a fab day and wonderful children and school.