How To Get A Fall Color Effect in Photoshop
1. Duplicate your image, in case you need to erase any of the areas you are going to change, to return to the previous state.
2. Go to "Layers" > Adjustment Layer > Hue/Saturation > "Ok"
3. You will focus on the Greens or Yellows, depending on the photo. Drag your Hues to the left, toward the reds and oranges. For this image, I have the Yellows on -33 and Greens on -43
4. It affected the skin areas, which I do not want. So, I have erased the areas I don't want affected, from the Adjustment: Hue/Saturation layer.
5. After erasing the Adjustment layer, the contrast between the new and original version was too drastic--she had a lot of green tones in her skin, from the trees around her. So, I adjusted the Color Balance on the 2nd layer, just to add a little more Magenta--this will vary, by the photo.
6. Lastly, I wanted it a little more warm around the edges. So, I used the Burn tool (set for Midtones on 50%), to create a very subtle vignette.