While I'm still getting my head around the logic of Layer Masks I can see their usefulness and possible application in many areas. Will be looking into some more tutorials to understand these more.
Texture onto portrait
Thoughts: Here I kept both images black and white. Strangely the concrete mural background looks more alive with this texture.
Using Layer Mask - Isolating Texture on Image
Thoughts: Here I decided to keep the texture in color and the portrait in Black & White so as to show more contrast and got rid of the texture from behind his glasses.
Using Layer Mask - Black & White with some color
Thoughts: This was created with a layer mask covering up everything except the lilies. I took this shot at Cornwall Park. It was one of the last things I saw after an afternoon of 'trying' to find 'Rule of Thirds' subjects to shoot. In the end it didn't really fit any of the compositional elements I was looking for but I was drawn to the subject matter. The additional editing into Photoshop seems to create further drama/emotion that perhaps wouldn't be there without the edit.
Using Layer Mask - Color Correction
Thoughts: While this Colour Correction on this image isn't perfect (the trees are way too golden) it was my first time playing in this area and it made a difference making the rainbow and sky brighter. Will need to work on a few more of these before I understand them.