I did try to implement advice that Vigee-Le Brun gave to her niece, (
http://www.batguano.com/Vigeeadvice.html) along with closely studying several paintings that she had done of Marie Antoinette.
When I began painting, I started out with paint thinner to block in areas so that they would dry faster. Later I used just a blending and glazing medium from Winsor & Newton.