Measure the height of the vase so you can trim the flower stems to fit inside completely submerged. Cut the stems 1/2 to 1 inch shorter than the height. For multiple flowers at different heights, cut the tallest flower and position others next to it where you want them to be. Cut off the excess so all the stems are even at the bottom.
Squirt aquarium glue on the end of the talest flower stem, and stick the glue end to the inside bottom of the vase. Hold the stem in place until the glue sets.
Repeat the gluing process with the next tallest flower until all the flowers are in the vase. Do not overload the vase with too many blooms; open areas are more attractive.
Examine the glass vase, with the flowers inside, from every angle to make sure the blooms are placed correctly and look attractive from all sides. Rearrange flowers as necessary. It is easier to adjust the flower placement before you fill the vase with water.
Fill the tall cylinder glass vase with distilled water up to 1/2 inch from the rim. Distilled water will not create bubbles on flowers and glass sides like tap water.