If you are just starting out with topiary, a tree that is already trimmed in a classic shape, such as the spiral or a double ball can be a quick and easy way to get going. You can learn about taking care of your topiary, maintenance pruning, and how to observe your plant with one that is already started. A boxwood cone and spiral are two easy to maintain shapes, and boxwood is a hearty, easy-care plant.
An easy way to create a topiary is to purchase or make a wire frame in the shape you desire. This works especially well with small plants, such as woody herbs that can be treelike without achieving the stature of a full sizes shrub. Select potted plants that are approximately the right size for your mini-topiary. Place them in an appropriately sized bedding tray, and settle the wire frame over them. Encourage the leaves to poke through the meshes of the wire. As the plants grow, gently trim them so that the wire shape emerges in green foliage.