2.Go to Layer->New Adjustment Layer->Hue/saturation. Apply the settings to match best with your image. I have used the following settings:
3. Now fill the adjustment layer with black color. Choose a brush with 0% hardness. The size of brush will depend on the image size. Choose white as foreground color. If you make any mistakes instead of using eraser, change the foreground color to black and make corrections.
Here is the final result: