I thought it would be a good idea to share some of the ressources and pages I tend to go to get some information about painting. Feel free to write me if you think some things should go in. Some links go to products with a price-tag on them. I don't want to advertise those, I just want to show what I know is out there.
Video Tutorials Level Up A lot of cool theory, overpaintings und interviews with industry-pros (you will find it under “Watch Sessions”). Don't miss the one about "Color Theory". It is really interesting and helped me a lot. http://www.fusroda.com/resources
This book is one of the evergreens, so you will probably have heard of it on another website. To me it is less of a "read-in-one-sitting" than a "look-up-when-I-need-to" - book, as it contains just too much information to digest in a short time. It goes from very general principles of light to very specific problems in painting certain subject matter. I really love it and I wouldn't want to miss it.
Drawing Basics and Video Game Art - Chris Solarski - 19,40€ http://solarskistudio.com/book.html I really like this book. It starts at absolute zero and goes to design principles. Some might find it a bit shallow at times, but I think it is just enough information to get somebody started.