** Daniel Smith's tutorial archives - their catalogs have had well illustrated and professional tutorials for years. Many are gathered here. The first place to look for advice.
**Scott Burdick's demonstrations - Burdick is a great portrait artist and his website has several demonstrations.
**Vigee Lebrun's advice on portraiture - The main part of this website is opinionated and full of formulaic ideas about art, but scroll down and you'll find an excerpt about portrait painting from Vigee Lebrun (17th-18th century portraitist). Very interesting advice from a different time and approach. It had never occurred to me to pay such close attention to foreheads.
Links to art tutorials including Scott Burdick
A group of art tutorials including an interesting one about using Scanners and Computers in Art
William Whitaker's website - an accomplished traditional realist includes some tutorials including one of the few good ones about grisaille
Links to art tutorials and info about a realist atelier
**About.com's painting info site - with some old master's info and other eclectic stuff, including a Page of links to portrait sites
Alexei Antonov's website - an egomaniac realist, but has a lesson on grisaille of a rose. Grisaille info is hard to find.
Nancy Doyle - several art tutorials, some of which are mostly advertising, but a decent one on art materials
**Art Q&A site - a large site with good info under Painting and Paints, emphasis on technical info
Foundations in Grisaille - Colored pencil demo of an intricate grisaille teapot
An artist's color theory Oil painting techniques - Portraits and other subjects
**Wet Canvas - huge website of art forums, including Color Theory and Luminous Skin and Limited Pallette and Studio photography lighting techniques
History of Painting Techniques - includes old master techniques - shadows, flesh tones.
Indirect Painting technique - Example is rocks under water
Art Show - Links to a number of painting, pastel, drawing, digital tutorials including some Daniel Smith
Real Color Wheel - a huge, rambling website including medium yellowing, complementary pigment lists, and a rather obscure main menu