- Create the lettering without any shadows
- Use a marquee to copy the entire set of letters you created <Ctrl + C>
- Using the fill tool in non-continuous mode, replace the color of the letter set with a different color
- Paste <Ctrl + V> a copy of the letter set onto the canvas
- Slightly offset the letter set from the underlying background layer letter set. This gives the shadow effect, without the need to manually draw in any of the shadows.
Bonus tip: You can also offset the letters both vertically and horizontally, especially for lettering that is a bit larger. This gives a pleasing look when the shadow is offset at an angle, instead of only vertically.