I have recently felt inspired to paint sunsets with beautiful deep reds. Unfortunately, my attempts always fail, with my skies looking more a bruised purple than anything else. The result is that what might otherwise have made a good painting is ruined. What am I doing wrong, which colours should I use - and how?

Ray Campbell Smith replies: Your letter suggest that you paint your skies last. Try painting them first. This is good practice since the way they turn out will strongly influence the scene below. You don't mention your medium, which would have some bearing on my advice. However, in general, you should aim for lighter, fresher colour, which will leave something in reserve for the deeper tones of your landscape.