Third on the "outdoor decor mistakes" list is ignoring the landscaping. A little bit of landscaping can go a long way toward giving your home curb appeal. You don't necessarily need a huge garden full of a variety of flowers - if you don't have a green thumb, an urn on either side of the door adds colour without taking a lot of work. Hanging baskets of flowers can be another low-hassle option. Stones and shrubbery can look great as well. A small fence can also add curb appeal - as long as you choose a paint or stain colour that works with the rest of the house.
And the last mistake, on the opposite side of the spectrum - excessive lawn ornaments! While one or 2 decorative items can add a bit of pizazz to your yard, an entire family of gnomes paired with a well (or 2!), a collection of pots, wooden cutouts, and multiple sets of windchimes detract from your home's look. A smaller number of well-chosen items will have more impact.