Here’s the video requested by all of you. I’m polishing the top of my slab coffee table. This is the process I use to achieve a very high gloss finish using polyurethane.
The first step is to wait for the finish to completely cure. After its cured, I sand it with 2000 grit wet dry sandpaper. Then using a buffing pad and some polish, I buff the top to a nice gloss. The final step is to finish the shine by wiping with a clean dry rag. This really brings out the shine. This is a simple process and has a great final result.   Check out the video to see how I do it.