Step 1
First, get the text you would like to have a 3D effect.
Step 2
Now duplicate this text and remove all of its Layer Styles. Set the color of this text to the color of the stroke on the original text. If you have no stroke just make the color of the duplicate text similar to the original text.
Step 3
Place this duplicated text behind the original text. Use your arrows keys and tap the Up and left keys. I tapped up 4 times and left 3 times and got the 3D effect.
Final Result:
