Here's some hints on how to make your fresh flowers last:
Take it Off!
Remove the paper wrapping - it can go in the compost - and take off the rubber band.
Cut about 1/2" off the stems at an angle to allow more surface area to drink water as well as ensure the stems don't sit flush with the bottom of the vase.
GIVE THEm A DRINK!
Fill the vase with cool, clean water. Clean water prevents bacteria from growing (which is what causes flowers to rot - yuk!).
If you can remember to change the water daily - AWESOME!
To keep your flowers fresh as long as possible, take out those fading flowers as they wilt so they don't spread bacteria to the flowers that are still loving life!
Keep them cool!
Find a spot away from sunny windows - your flowers will last much longer in a cool spot.