I used a jar lid to make some circles on the paper. My father always said "use the right tool for the job." I have my own saying, "use whatever's closest so you don't have to get up and go looking for stuff.
I made a few too many circles and a couple irregular shapes representing nothing in particular.
Using a wide charcoal stick I drop a shadow below and a little to the left of each object. This suggests that the light source is above and a little to the right.
With the same charcoal stick ( you can use a graphite pencil or anything else you like, but I like charcoal) I dropped in a shadow onto each object. But you'll notice that the circles on the top row are shaded in their low left area while the circles in the second row are shaded on the top right. What gives? The top row are opaque objects while the second row are transparent.
Now I use a sharper pencil to create some reflections. Reflections don't behave like shadows. Shadows and rays of light move in whatever direction they move without regard for your point of view. Reflections on the other hand always come straight towards your eye.
So if the ball on the top left is a dull stone, but the one on the right is a chrome plated ball then the stone one has no discernible reflection on its surface, but the chrome has nothing but reflections.
So let's imagine you're looking at this ball on a wooden table at the park. There's an open field all around you but a tree line in the distance behind you. The curve of the ball will compress the reflection to a thin dark line at its point closest to you but will expand as it moves to the sides. But it will continue looking like this weather you move the ball or yourself.
To give the paper some tone I smeared the whole page with a paper towel.
Notice that the two transparent balls have a light spot on the ground below them because the light shines all the way through them and onto the ground. Also the ball itself doesn't seem to have a shadow on the low left because light is scattering all around the interior surface of the glass ball.
Now using a white chalk I exaggerate the highlights even more. This makes it all the more shiny.
Just for the fun of it I got a couple colored chalks and added a touch of blue on the chrome things. Not much, and keep it up near the top. The color is concentrated at the edges and diluted by the over expanded reflection where it bulges towards you.
Also a touch of brown at the bottom reflected from the ground. I added this tiny amount of color to illustrate what a small role color plays in creating the illusion of metal or glass. Most of it is accomplished in black and white, color has very little to do with it.
Many beginners including myself long ago tried to depict things like armor with silver paint. Wow did that look wrong! And it's really quite easy to do it right.
I draw way better than I teach, but I hope some of this made sense to you. If you'd like me to clarify some part of that please let me know even if you discover this blog a hundred years from now.