Thanks for the compliments.
Yes, the sky looks pretty but is quiet simply made: a full ocre yellow undergrond and on top I painted just with 1 colour on the ocre yellow: wet in wet. With a lot of brush load and pressure the blue paint mixes with the ocre yellow which gives an ocean warm aqua blue and swirl/movement in the air.
We all can learn from our old masters just by trying to copy an artwork of them to get the right feeling of colours and brush strokes. About 20 years ago I copy painted a Van Gogh painting in oil on canvas, that felt very special (http://www.dagjeweg.nl/img/dagjeweg/...nacht-6457.jpg). So now and then I go to Amsterdam to visit the Van Gogh museum.