Please keep your flowers away from direct sunlight and drafts for longer vase life. Giving your flowers fresh cool water and a fresh snip every couple of days will also help with longevity.
Tulips and other bulb flowers do not like flower food, so it is not always necessary. Greens like to be sprits, but getting water on some flower blooms can cause spotting and rot. It is also helpful to have a proper vase size, trying to put too many flowers in a small vessel that can crush stems, or cause rot.