A lot of people forget that you need to take care of your wreath. By a lot of people, I mean me. I just hang it and let it go, but there's a lot you can do to keep it looking amazing all season!
Buy a freshly cut wreath.
Hang it in the right place. Placed outdoors and out of direct sunlight will help them last longer.
Don't forget to spritz or mist your wreath.
Cover up the wreath at night. Covering the wreath in plastic will help keep the misted water on the surface of the wreath at night, so it stays fresh for longer.
Try an anti-transpirant spray. Yeah, I'd never heard of that either. These sprays are designed to protect foliage from heat, sunlight, wind burn, and other elements that might cause it to dry out too quickly.