Cut flowers never seem to last as long as you want them to. To keep your flowers looking fresh a little longer, you could use the little packet that comes with many bouquets, or if you want something better, try an aspirin. It is believed that aspirin helps keep disease at bay so that the flowers stay fresh longer.
Crush an aspirin. Place the aspirin in a spoon and place another spoon on top. Squeeze the spoons together to crush the aspirin.
Mix the aspirin into a vase full of water, and place the flowers in it.
Trim off a bit of the stems each day to keep the flowers drinking. The stems seal themselves up over time, which keeps them from getting the water they need to stay fresh.