It is most helpful if you chose an image with a pose that is graphically interesting. Those images stand on their own! For this demonstration, I chose this image of Andrelica. I am also fond of inscrutable facial expressions, and this is one of her signature looks:
The first step is to simply retouch the image, resulting in something like this:
Here is how the Layers Panel in Photoshop looks:
I used the Lasso tool to lasso the eyes and put that selection on it's own layer, named it Eyes Lighten, set it to the Screen blending mode and set the layer opacity set to 30% or so. The pupils and area surrounding the sclera were masked out. The Eyes Dimension is simply painting 50% gray on the iris, setting the layer blend mode Color Dodge, and reducing the layer opacity to 40% or less. I then used a Hue/Saturation adjustment layer to add a little more color to her lips. The layer opacity was set at 40%. The plug-in Portraiture (by Imagenomic) was used to smooth out the skin. I use the Medium setting for big files taken with a 36 MP sensor and the Normal setting for smaller images taken with a 12 MP sensor. Though Portraiture has its own mask, it is not perfect. Her eyes, lips, hair and swimsuit were then masked so they would stay sharp.
A composite layer was created by holding down Option and selecting Merge Visible from the Layer Panel's flyout menu. This was labeled Extract because it will receive the mask to eliminate the background. There is not much contrast between her hair and the seamless background though, so here is a simple trick. Duplicate the Extract layer, then Command-M to get a Curves adjustment. Raise the midpoint up to lighten the entire image:
This looks terrible, but now there is more contrast between the gray background and her hair. This is a temporary layer for use in getting the mask. Here is how the Layer Panel appears:
At this point I activate the Topaz Remask plugin. I discussed Tips On Using Topaz ReMask 5 To Mask Models in this blog on September 30, 2015. Once I am done, ReMask 5 returns a mask on the Extract copy layer. Drag the mask to the Extract layer and delete the Extract copy layer:
I then will Option-click on the mask to see a black and white version. Take a white Brush set to the Overlay blend mode (in the Options Bar) and paint over the hard edges, staying away from the hair. This will "firm up" the white edges of the mask by filling in any gray areas with solid white. A black Brush set to Overlay will eliminate any gray areas in the black part of the mask. This is especially useful in acute corner areas. Save the file as version one. I like to keep a file with the original mask untouched. In the next instalment I will discuss the goals of what we are trying to accomplish and how to add the sky and water.