Polymer clay has many values, and I went over them in Polymer Clay Basics I, so go read that before continuing this one!
Add-Ins can help convey an aesthetic that brings your piece together. Glitter, bubble beads, and much more can be added to help your sculpture shine. Glitter can be mixed in to the clay, or patted on top, depending on your preference. Bubble beads can be pressed in to the outside of your sculpture to give a magical touch. You can also add pigment and mica powders to color your clay, or give is a subtle shimmer.
Armature is an essential part to any large sculpture, to help it stay together. Wire can be used inside of smaller, thin pieces to help them stay on and not break. A combination of wire and tin foil is also a good idea to have when blocking out the base, or skeleton, of a large sculpture. Tin or aluminum foil can be used to wrap around the wire to bulk it up and save clay.
Tools are not essential, but make the sculpting process a lot easier. The most basic tools to have are a needle tool, a smoother, and at least one ball tool. A needle tool is simple, and you can make one by cutting the sharp part off of a safety pin and pushing the point into the end of a hot glue stick. Other household objects can be used as well.
Even if you are a complete beginner to polymer clay, and don't have many tools, these tips, tricks, and basics can get you started on a new crafting medium.