The first one: choose the blue sky and use the photo filter. Image, adjustment, photo filter. According to the need to change the situation, select and adjust the filter type and color density,,,
The second is to select the blue sky, execute the commands of image, adjustment and color replacement, and then draw the blue sky with a brush ~ (remember to set the opacity ~ ~), otherwise the color will cover the whole image.
Third, select the blue sky, execute the command to adjust the hue saturation of the image, open the dialog box, and adjust the sliders of hue, saturation and lightness until the color is satisfactory.
The last one is the simplest and most convenient.