Print words on basic white paper in mirror image form, lay them on wood. With a damp paint brush wet the paper on top of the words. Use the cap of a sharpie to rub on top of the letters to help them transfer, then remove the paper.
Buy a mirror. Put letter stickers on it. Paint over the whole thing. Peel off stickers. (use canvas instead of mirror. Paint canvas what color you want your letters to be first, then letter stickers, paint over, peel off)