You will be surprised. On average, 75% of the electricity used to power home electronics is consumed while the products are turned ‘off’. How to avoid it? Simply by unplugging the device/appliance or using a power strip and turning the switch off will cut all power off to the appliance. Don’t forget battery charges, those will also draw electricity.
For clocks, try using batteries instead (preferably rechargeable batteries). Usually clocks running on batteries should run for about a year.