Add some contrast
Back in the Layers palette, add another Curves Adjustment Layer. This time, instead of dragging the curve downward, click in the top quarter and drag up, and in the bottom quarter and drag down, making an S-shape, which will add contrast to the image. The contrast may be too strong in some places, but using the attached mask we can control its intensity as before. Using a large, soft-edged Brush, paint Black into the mask to decrease the effect of the Adjustment Layer. Here, I masked out most of the sky and some parts of the foreground, which had become too dark.