Showers usually use less water than tub baths. Shower for less time. Even when washing hands, don't let the water run. Wet hands, turn off the water while soaping and scrubbing, and turn it on again to rinse. Use a moisture meter to determine when your house plants need a drink.
More plants die from over-watering than from being on the dry side.
When shaving, pond hot water in the basin instead of letting the faucet run. For cooking most food, use only a little water in the pot and put a lid on it. Not only does this method save water, but food is more nutritious since you don't pour vitamins and minerals down the drain with the extra cooking water. Buy products with the least packaging. Use reusable containers.