I save all of the water from my washing machine (on the most economical setting it is around 60 liters), and use it to flush my toilet. I store it in 25 liter containers and add a little bleach to stop it from smelling as 60 liters is enough to flush for a week (if I let the yellow mellow).

I have also unplumbed the u-bend from my sinks, and put buckets underneath to collect the water also to use in the toilet and on the plants.

I take showers with a small jug and am very careful with washing up water. Like this I can use roughly 20 liters of water a day.