Turn off the water supply valve behind the toilet
Flush the toilet to empty the tank and bowl as much as possible
Hold down the flush handle to remove more water from the tank
Use a sponge, cup, or turkey baster to remove remaining water from the bowl
Soak up leftover water in the tank with towels or a sponge
If needed, use a wet/dry vacuum to remove the remaining water
Close the shutoff valve after the water is drained
Disconnect the supply line only if necessary and after placing a bucket underneath