If you don’t know exactly what you’re trying to accomplish within a photograph, you could spend many hours in Photoshop trying filters, masks, adjustment layers, and other tools, and you could still end up with no improvements. In fact, you might even end up with a lesser image than you started with. Photo retouching is a very subtle craft that requires not only Photoshop expertise, but also a more general attention to detail and an eye for color and contrast.
shows several techniques (as well as his thought process) during the retouching on one of these photographs. He uses the healing tool and the blending of layers to add some subtle improvements to his carefully composed image. Rather than polishing away all of the human imperfections of the model, Mike uses methods that preserve the authenticity of the image while making careful augmentations to color, contrast, and tone.