Idea 1 Testshots Editing Steps

Step 1

Firstly, I went to

Image>Adjustments>Levels

and moved the points to each side of where the histogram extends to correct the tones in the image.

 Step 2

Next,

Image>Adjustments>Curves

to brighten the colours in the photo. I dragged the line at different points to form an 'S' shape.

 Step 3

Lastly, I selected the Marquee Tool from the toolbar on the left and dragged it around the entire image. I put the pixels on 200 as I only wanted to darken the very corners. After that, I went to

Select>Inverse so that I was only working on the corners, not the middle and then adjusted the curves.