The blending worked really well. I used a bit of clear medium with all the colours and it seemed to make them last longer, flow better and blend more easily.
The painting process was as follows:
1. Prime the canvas with a thin coating of yellow ochre.
2. Paint in the sky using various tints of Cobalt Blue Hue thinned with clear medium.
3. Paint in the clouds using Titanium White plus greys mixed from primaries.
4. Draw in the outline of the hills with pencil.
5. Block in the main light and shadow areas on the background hills.
6. Block in the foreground hills and then move straight on to finishing this area.
7. Go over the background shadows adding texture with darker and lighter areas.
8. Paint in the light areas of the background hills.
Considering this is only my fourth ever acrylic landscape I'm pretty happy with the way it's turned out. This one I think is good enough to sell.