first thing's first, as soon as you receive them, fill the water in your vase up so all stems are hydrated! placement wise keep them in a cool spot, away from drafty places, and out of direct sunlight. want to get the most from your stems? here's how to maximize longevity:
keep an eye on the water level, making sure all stems are in the water
replace the water in your vase every two days
remove individual flower stems as they wilt (some flowers will last longer than others!)
trim the stems, at an angle, every two days