Use a pillow sham set to dress up standard pillows. Remember to take shams off at bedtime, though, so you don't wrinkle them as you toss and turn during the night.
A standard pillow sham is rectangular and fits a standard American pillow, generally 20--by-26 inches, while a Euro sham fits a square 26- by-26 inch European pillow. King-size shams measure 20-by-36 inches. Shams are usually sold in sets of two.
If you want to coordinate all your bedding, you can buy shams in sets that include matching sheets and duvet covers.