Hold off for a full load. This saves water and electricity! The average volume of water for a single load of washing is 150 litres for a top loader and 80 litres for a front loader.
Read the manual for your machine to find out which cycles are the most water efficient (usually eco cycle).
When shopping for a new washing machine, use the water efficiency labelling scheme (WELS) to help you choose. Just remember, the more stars on the WELS label, the more water efficient the washing machine is.
When soaking clothes, use a bucket instead of the tub so you can chuck it on a plant that needs some love.
Slow the flow! Consider installing flow restricting aerators on your sink taps. You’ll save water without even noticing!