Prepare your water using the flower food packet you receive with your flowers or bought at your local flower seller. Follow the manufacturers directions exactly, too much or too little flower food is NOT A GOOD THING! Make sure to measure the volume of water your vase holds and mix the appropriate amount of flower food into the water.
Using cold water or ice water (36-40 degrees Fahrenheit) is preferable to warm water. Bacteria growth is reduced in cold water and it has been proven that warm water does not make flowers open faster. Warm water will cause faster bacteria growth, making your flowers die faster.