Have you ever received roses and one or two drooped or seem to fall over quicker than the others?  Well this will help.

1.  Start by filling a clean vase (disinfected as germs kill flowers) with water (not softened). Bottled if need be as softened water shortens the life of a rose.  
2.  Add your floral food according to package directions.  (Most florists will sell these in small packages)  
3.  Remove leaves from the lower stems as leaves decay under water and cause rose stems to clog.
4.  Use a sharp knife or scissors (make sure they are disinfected also) and cut 1" off the bottom at an angle.  Put quickly into vase of water.  You have 2 seconds to put the rose into water as the stem will seal off and not drink.  Many florists cut their flowers under water for this reason.

.If your rose bends and looks like it is wilted after using the above steps, remove the rose from vase, fill a small garden tub with water, and cut 1" off the bottom of rose again and totally submerge your rose in water.  Shake the rose under water until air bubbles come out of the rose head.  Stand up in the water until the roses has drank and head has started standing. This works for me every time.  During holidays, when we have 1000 roses delivered and 50 or so are not responding to the care, we use this process and save 99%.

The above part about the rose we shown to me by a designer who had been in the busy 50 years ago. I have always succeeded in getting a rose to drink by shaking the air out of the rose head under water.

Keep your flowers away from the heating and air vents and also never set them on a TV.  Every three days, empty the water, wash your vase, cut roses and put into vase.