|Adding Wooded Foothills
"Layers" - "New Raster Layer". Call the layer 'Foothills'
With the Airbrush tool set up like this
Choose a colour with green in it. I chose #657b75.
Paint some foothills across the page.
Then fill in to below where the horizon will be.
With the Smudge tool set up as a horizontal line like this.
Drag the top of the hills up to make a tree line.
I have zoomed in to show you what I mean.
With the "magic Wand" select the foothills
"Adjust" - "Add/Remove Noise" - "Add Noise"
Using the Lighten/Darken tool on a very low setting darken around the shady sides of hills and maybe add closer hills.
Finally shape the bottom edge (the shore line ) to make some look closer.
In the Layers palette activate the background layer.
This is the layer with the horizon on it.
With the "Magic Wand" set at 0 Feather and Antialias not checked click in the lower section of the picture.
Activate the Foothills layer.
With the eraser tool set up something like this
Shape the bottom edge.
With the "Airbrush" tool set up something like this. Colour #cbcbab.
Paint some beach along the waterline.
Next : Adding Water