It's a very simple system really. Everything that's important goes in a box throughout the year. When tax is due to be done I go through the box and throw everything that isn't important but has still managed to end up in the box onto the kitchen floor.
My cat thinks this is brilliant as she gets so many new things to play with (until I scoop it all up and put it in the bin/recycling) and I find it a good stress release from my bad filing skills. XD
Urg, first year doing tax online. Very stressfull.