Picket fences are available in a variety of materials including wood and plastic. Making a picket fence out of wood allows you to customize the shape of each picket or slat. For instance, a traditional picket fence has points at the top of each wood picket, but you have the freedom to make it round or include decorative cutouts. If you do not have the equipment to create custom wood slats, work with a home and garden department store or individual crafter to get the shape you want.
You have a couple options for lining up the pickets including spaced out or flush. A plastic picket fence does not require much maintenance after it is installed except for a little cleaning, but a wood fence requires weatherproofing and future maintenance to maintain the color and shape.