Numero uno, I start with duplicating the background, I don't want to ruin the original photo.

I began with cropping the photo using the crop tool

Once cropped, I got onto selecting the the traffic light using the magic wand tool. I used other tools such as the lasso tool to refine the selection.

Once I selected the traffic light, I inverted the selection as I wanted to focus on editing the background.

I didn't want a background with buildings in it, favouring a clear blue sky. For this, I used the cloning stamp tool which is the best tool for this job. I had to hold the ALT key and click on the part of the photo I wanted to clone onto another part of the photo. The photo above shows the outcome of this.

 The selection path came in handy as it made sure I didn't clone over the traffic light as you can see.

A common occurrence in cloning is that eventually you end up stamping something you didn't originally choose to clone. This is because when you clone, the part that you choose originally deviates as you stamp in different positions on the photo. To resolve this, you simply reselect your clone stamp by holding ALT and clicking.

Eventually, This is how the photo looks without the building in the way, just pure clear sky.

My selection path was obviously shabby and this was not part of the traffic light, it just happened to be black as well which the magic wand tool interpreted as part of the traffic light, as did I at the time.

Unhappy with this, I decided to crop my photo once more.

Once I finalised the composition, I worked on changing the colour of the green man. To do this, I went on Image > Adjustments > Selective Color. Here I chose to manipulate cyan colours, changing the values of CMY and black. This resulted in the green man turning blue.

I also changed the CMY values for greens and blues to enhance the saturation of blue.

I flipped that canvas vertically and this is the end product.