Improve the lighting and colour of a landscape!
Use Levels or Curves to add some light to the shadows and midtones; we focused on Levels and the midtones.
Apply Image>Adjustments>HDR Toning, boosting Detail and Strength. Be sure to balance shadows and highlights.
Create a stamp with Cmd/Ctrl+Opt/Alt+Shift+E. Apply Filter>Other>High Pass with Radius: 30px and set to Soft Light.
Add a Vibrance adjustment and increase the colours to make the sky stand out. Adjust the contrast if needed.