Pull a guide down to mark the centre of your image and using the marque tool select and delete half your image. Deselect and then Edit > Transform > Flip Horizontally to get the shoulders and eyes exactly the same and in perfect synergy. Now select the Delete tool and remove areas down the joint line to make it look more natural.
Now merge your layers by using merge visible in the layer menu pallet. Then duplicate this layer again and apply Filter > Blur > Surface Blur to clean the skin tones and create a perfect complexion. Experiment with the settings to get the feel you want, and then also experiment with the layer opacity.
Walk away from your computer and get out a pen. Start scribbling and generate a pattern in the style you prefer, make it relatively complex and then scan in your image at a high resolution. This will be the main factor in the feel of the piece so get it right and don’t skimp on time on this stage.