Clean your vases: Before filling your vase with fresh flowers, make sure to wash it well. Bacteria builds up in the vase and can impact the longevity of your flowers. Don't be afraid to use a sponge and some detergent. Even a drop of bleach!
Strip off leaves: Leaves that are submerged in water will cause bacteria and compromise the life of the arrangement. Strip off anything that will be below the waterline.
Make the arrangement in your hands: By making the arrangement in your hands, you have more control and have a good idea how it will look in the vase.
Cut stems on an angle: Cutting stems on an angle allows for more water absorption. Be sure to use something sharp as dull blades can crush stems, making it harder for flowers to get water. Cut your flowers just before putting them in water; limiting their exposure to air makes them last longer.
Change the water: Flowers like fresh drinking water, just like you! Change the water every couple of days to ensure a longer-lasting arrangement.