Colours to use: Lemon yellow, permanent red / cadmium red, prussian blue - unusuall colour for a landscape but you can get lots of interesting shades by mixing

stcergue sketch   stcergue4   stcergue3
Sketch out composition and apply white gouache to the centre above the path. Dry well   Paint the sky (upside down) with prussian. Paint very carefully over the area where you have applied the gouache, try not to disturb the gouache layer. Paint in the background trees with mixtures of the 3 colours   With a damp tissue blott out the trees and the mist shapes. Change your tissue often  
stcergue2   stcergue final    
Start to paint in the foreground trees paint with different colours and tones. Trees are not 2 dimensional and branches will get darker as they come towards you   Continue painting the tress and add the foreground rocks and vegetation