Anyone that paints needs to be reading Jim Gurney's blog the Gurney Journey. Daily. It's such a deep fountain of information, I've seen seasoned pros get sucked into it for hours. Gurney has hinted at collecting the posts and making a How-To book of it, and so he has:
"The book is called Imaginative Realism: How to Paint What Doesn't Exist. It’s a big book: 224 pages, 400 illustrations. Andrews McMeel will be doing a beautiful job of production, and they are keeping the price down to $24.99.
This is the main project I’ve been working on during the last year. The material comes from my art school lectures and also from this blog. The reason I wrote the book—and this blog—is that there’s a lot of information that I think is crucial to imaginative picturemaking but I’ve never been able to find it in how-to art books."