When dealing with roses, make sure you have sharp shears so you can get a clean cut. When ready to arrange, cut above a node and always cut at an angle so the stem can drink the most water. Make sure you have plenty of water in your vessel and check it daily, filling as you need. After twenty years of doing flowers, the single most overlooked thing restaurants and other accounts do is forgetting to water in the first couple of days. Then, when the flowers begin to wilt, they add more water. More times than not, this is too late and they won't come back. If you notice a bloom or two wilting a bit, take it out and recut the stem.