1. Create a new document (Ctrl+N) of your own size.
  2. Select Text tool and insert your desired text.
  3. Select the text you just created. Then Edit->Duplicate (Ctrl+Alt+D) to duplicate your text.
  4. Click Modify->Transform->Flip vertical to make your duplicate text upside down. For more realistic effect, make sure the height of the upside-down text smaller than the original text.
  5. Select your upside-down text, in the properties panel, click color fill->Fill Options and from the dropdown select Gradient and Linear. Reduce the Opacity to 60.