Using a PL Filter
One more factor that really enhances the brilliant autumn colors is the fresh and beautiful clear skies. Nothing says autumn better than a landscape composition that includes the clear blue skies and the reds and yellows of leaves. However, if you compensate the exposure to emphasize the foliage colors, the color of the sky in the picture can seem brighter and more faded than what you actually saw. This problem can also be solved by using a PL filter.
Enhance the color of blue skies using a PL filter
Using a PL filter you can emphasize the color of blue skies. While checking the monitor, turn the filter frame until the color of the blue sky seems deep enough and then take the picture.