http://www.dgtouch.com/photo-retouch/
Follow a few of these to learn different techniques, and then put your creativity to work and find some ways to use lighting effects, resizing shape and remove a blurred or smeared mark on the surface of something on your own.
Read more at http://www.dgtouch.com/  
                    
                    photoshop
                    photoediting
                    graphicdesign
                    productretouch
                    dgtouch
                    photoretouch
                    imageretouch