The following video demonstrates how to draw a reflective sphere...
Learning how to draw reflective surfaces can be tricky. This page will give you a couple of pointers for drawing highly reflective surfaces. It doesn't have to be hard to draw things that are reflective when you keep a couple of things in mind.
The first thing that you will need to consider is that reflective surfaces are just reflections of what objects are around them. So if anything is sitting next the reflective object that you are drawing, those objects will need to be included in the surface of the object that you are drawing.
The second thing to consider is that convincing drawings of reflective objects include high contrast and hard lines. What I mean by this is that reflective surfaces seldom have smooth gradations in value. Instead darks are usually positioned right next to lights and there is little to no transition between the two.
Another thing to think about is the form of the object that is reflective. For example, a sphere will curve the reflections seen in the reflective object, while a cube will not distort the reflection as much.