Prepare shoe for polish.
Brush off any dust and dirt on the shoe. Make sure to get into the crevices and work out as much buildup on the shoe as possible. You do not want to polish dust into the shoe as it'll dry and make the shoe look unsatisfactory.
Take the top of the polish can, and pour a small amount of water in it.
You may now insert your shoetree if you have one, however you may use your hand if you do not have a shoetree. When you start to polish, simply insert the idle handle into the shoe to keep the toe stiff to your pressure.
Take your old rag or underwear and wrap a small portion of it around your pointer and index finger. You will be using these two fingers for polishing. Run the rag through the polish and get a decent amount on the rag. Then dip the rag in water to loosen up the polish.
Take the rag and make very small, circular strokes with your rag. Reapply polish and water as needed, but be sure not to cake the polish on the shoe. While you are shining, breathe onto the areas you are going over, and polish the condensation that ends up on the shoe into the surface. It'll help the polish absorb into the shoe, and you will notice the shoe start to shine up.
Repeat this process until you shoe the entire shoe, mindful to keep breathing onto the shoe as you move. This process takes a long time, depending on how much of a shine you are looking for.
A decent shine session is about 30 minutes per shoe.
Edge the shoe.
Take your toothbrush (hopefully one you do not need!), and gently run it through the polish can. You do not need to apply water to the brush.
Run the brush along the edge of the shoe where the sole is stitched to the shoe. As you wear your shoes, you will notice dust and dirt start to discolor the top of the sole. This edging will return the sole to it's black color, blending it in with shoe, making it look superb.
This is a short process...30 seconds to a minute.