One evening I saw a particularly beautiful sunset, which I to no avail tried to capture on my phone camera. After the third photofail I just grabbed my paints, and finally got a satisfying picture. Usually skies and clouds are my nemesis (and you can see how I ruined this one with inappropriately watery glaze). I like this one, however.
Pigments used: indanthrone blue + cerulean PB35 for the sky, quin lilac PV19 with a touch of quin magenta PR122 for the clouds. I could have probably just used PR122 and some warm blue mixed in different proportions, but I wanted to keep the colors as saturated as possible, so opted for four different pigments instead.
After scanning this, I found out the remedy for the watery glazes. You see that thin annoying deposit of pigment that marks the edges of the puddle that had been there? You can just lift these things with an almost dry brush after the painting is completely dry. I tried this method with this very sketch, and it works. Be careful to not overwet your brush!!