Create a selection, save it as a layer mask, manipulate the opacity of the mask with adjustments and apply some complementary adjustments on teh colro channels...
You may not even need to mess with color channels.
As Mylenium has said, you'll need to learn about layers and masks, and especially about partial transparency, which works well for the windshield.
The shadow underneath will have to be handled separately. I cut it out and put it in its own layer, using Multiply blending to believably darken the grass.