Choose colours lemon yellow, raw sienna, Burnt sienna, ultramarine. Start with some quick sketches, I like the unusual format but crop it shorter if you want.

venn ottery sketch2   This is a quite tradition composition - if you like classic choose this   venn ottery sketch1   This I think has too many trees on the left side - which could distract from the building
atmo tree1   atmo tree2   atmo tree final   founex port final
Roughly sketch the composition. I decided to use sketch 2 but make the composition portrait. Sketch 1 is more traditional.  

Paint clean water on the top of the composition above the building. Paint on ultramarine for the sky then add raw sienna and burnt sienna allowing the colours to merge wet-in-wet in the middle section before adding greena nd blue at the lower half. Paint fast don't over think it. It will look very dark but will dry 30% lighter. Drop in more sienna + blue while the paper is wet, BUT once it starts to dry results can be unpredicatable, this is when you get cauliflowers! Dry completely - paper should be flat.

 

Paint in the building letting the colours run into one another. Add the trees to the left. Paint the roof roughly with vertical lines that mirror the angle of the roof.

Paint the shadows on the fir tree, basically they are irregular horizonal lines

  Add more darks to the shadow sides of the building. Use a rigger to make fine lines around the windows and add shaows to the tower