Cut cut flowers correctly
Proper cutting is very important for many cut flowers. Basically, the flowers last longer when they are cut under running water. The cells can then be soaked with water immediately.
Besides, the best time to start cutting is in the morning. When the flowers are purchased in the evenings, they can be put into the water overnight to the flowers. And then they are briefly cut again in the morning.
On the other hand, for fresh roses you have to cut fresh every evening. My grandmother always held roses briefly in boiling water after cutting. And tulips last longer when pricked deep with a darning needle. Incidentally, the water covers tulip stems only four fingers wide and is renewed every day.