What I did...

Finishing touch: A brilliant tip that I learnt recently, is that once you are pretty happy with the final product and the layers are working well together. Unlock the original layer at the bottom (click on the lock icon near the top in the palette). Duplicate the layer by dragging it to the page icon at the bottom of the layers palette. Drag the new layer to the top of the stack. Set it to the 'overlay' mode and drop it's opacity. The effect brings out the contrasts in the image very well.

Below is what I finished with – which is a tame version of what can be achieved. You have a choice, either make minor enough amends to retain the original image as an interesting picture, or distort it into a fantastic unrecognisable background texture.

layer 0 copy = overlay layer mode @ 60% opacity
glass = screen layer mode @ 30% opacity
coloured pencil = difference layer mode @ 100%
rough pastels = hard light layer mode @ 100%
layer 0 = normal @ 100% (I chose to keep it toggled on)

Finally!

Hopefully you will have saved your image throughout the process of working on it. The layered document creates a .psd file which is a fully editable Photoshop version of the image and can be worked on more as and when you want to. Go to File> Save As... and choose the file format that you would like to save it as from the dropdown menu.

The End