This is probably one of my favourite projects to do. I usually hand out a selection of well known paintings - Van Gogh is often a good choice due to the colours. The children first sketch out the painting and then get to ripping up tissue paper to replicate the painting. Thinking about layering colours to get different tones. Use plenty of pva glue as you cover it and you get a very hard and shiny finish. The final touches are a little bit of black sharpie once dry.