Hello.
Thanks for sharing the video.
Personally, Like Ged mentioned, I would just add the cup to an existing photo and save some time and effort on the cloning. The lighting, shadows, and reflections can be added without much effort. At the very least, I would have placed my cup on some monofilament fishing line for the photo making cloning a cinch.............or taken a completely different photo of the cup.
I was also very confused by the Create new layer and Stamp Visible layer when Cmd/Cntrl + J would do the exact same thing. If this were intended for beginners, wouldn't explaining the simplest of ways to accomplish something be better?
By your own admission, your cloning could use some work. The Clone Stamp tool doesn't memorize it samples. You should always clone on a blank layer, this makes it much easier to remove mistakes later. I think you had your Clone Stamp brush too soft and this is why you had the fuzziness and OOF edges.
You can remove the pixel grid (on zoom) by going to VIEW > SHOW > deselect/uncheck pixel grid.
Your tutorial is a bit incomplete when you discuss making a mask around the cup and not explaining. Although you did not need to sharpen the cup as this made it look photoshopped in the final image, it looked better before.
I think you have potential but your still in the learning stages with Photoshop. Your voice and presentation is good even though you said some odd things and didn't explain some steps very well. My general opinion is that this tutorial could be more confusing for beginners than it needs to be but it manages to cover the technique well enough to get by.
Don't give up! Practice, practice, practice!