1. Start off by downloading this image and opening it in Photoshop.
2. Then, duplicate the layer and set the resulting layer to grayscale. Then, with a medium soft brush, mask out everything but the sky (it doesn’t have to be perfect), as shown below:
3. Next, we’re going to add some better clouds to replace this rather dull sky. Download this image and position it as shown below over the image and mask away everything but the sky. Set the layer’s blending mode to Darken.
4. Then, we’re going to create a vivid photographic effect that will bring out the best in this image, by adding several adjustment layers as follows:
Add a new Hue/Saturation… adjustment layer with the settings below:
Add a new Channel Mixer adjustment layer with the following settings:
Add a new Curves… adjustment layer and modify the RGB curves as shown:
Add a new Selective Color… adjustment layer with the settings below:
Finally, add another Hue/Saturation… adjustment layer:
At this point, the image should look something like this:
5. To add a dark vignette effect, create a new layer and paint on its edges with a very large, round and soft brush, to get something similar to this:
6. Flatten the image and add a dark gray border (exact color: #212121) by going to Image -> Canvas Size… and using these settings:
7. Go to Filter -> Sharpen -> Smart Sharpen… and use the following settings:
The final result:
