Proper trimming is essential to extend the life of roses in a vase. Start by removing any leaves that will be submerged in water to prevent rotting. Cut the stems at a 45-degree angle using a sharp knife or pruning shears, as this improves water absorption. Trim the stems under running water to avoid air bubbles, which can cause the roses to wilt faster. Repeat the trimming process every 2-3 days, changing the water to keep it fresh. Use cool water and consider adding flower food or a few drops of lemon juice to enhance freshness. By following these simple steps, you can enjoy the beauty of your roses for much longer.