Turn all taps off correctly. This applies to the home, and any situation in which a tap is used. Much water is wasted on a daily basis, simply through dripping taps and faucets that were accidentally left at the wrong setting.
Drink water from a water filter, instead of purchasing bottled water. The filter provides the same cleansing benefits, while you are only taking what you need, and avoiding pollution from the bottles.
Turn off the tap while you are brushing your teeth. This task alone can save up to 25 gallons of water a month
Measure water carefully when preparing it for use. Do not take more than you need when preparing things like coffee or tea. Use solely the amount of water that you will be consuming, so you won't have to pour any down the drain in the end.
Wash clothing in cold water. In situations that would typically require hot water, like when an item is stained, simply presoak the item in hot water and then wash it in cold with everything else.
Water plants with a bucket or watering can, as opposed to with a hose or sprinkler. Hoses and sprinklers supply much more water than needed for such tasks. Simply fill the chosen container with water, and pour it over your plants. If there is any remaining, leave it for the next watering session.
Reuse water whenever possible. For example, you can save water that has been boiled, or used to steam food, to make sauces and even to wash dishes.