Soft Focus

Glamour photographs and portraits of women are often done in soft focus. In a studio the effect may be achieved with a special lens or soft focus filter that slightly blurs highlights in the image. You can come close to this effect with the Gaussian Blur in Photoshop.

Original
Red lips
Gaussian blur
Sharpen eyes/lips/hair

The above portrait was retouched as follows:

Red lips. To give a healthy glow to the model's lips, add a Curves adjustment layer. Initially the mask adjacent to the Curves icon in the Layers panel is all white and Curves apply to the entire image. Invert the mask (Ctrl-I) so the mask is black and nothing is selected. Paint the lips with a soft-tipped white brush to select the lips. For more feedback, Ctrl-Shift-LeftClick on the mask to toggle a ruby mask. Use shortcut keys "[" and "]" to control brush size. After making the selection, increase the contribution of red and blue in Curves for more vivid lip color.

Gaussian blur. Duplicate the original layer and apply a substantial gaussian blur — about twice as much as you think you'll need. Reduce opacity of the blurred layer to 30-50%.

Sharpen eyes/lips/hair. Apply a layer mask (small button at the bottom of the layers palette) to the blur. With a black soft-tipped brush, paint the eyes, lips, and hair in the mask. This makes the blur transparent and allows the sharp base image to show through.

A strong blur with a large radius that is reduced in strength will yield a more satisfactory effect than just blurring the image directly. Note that you can also reduce blurring in the Edit > Fade menu immediately after applying the blur. However, using layers and varying opacity facilitates changes at a later date.