Pick a master artist and a skill level. You'll be taken straight to that artist's page — history, reference image, supplies, and a step-by-step DIY project in their style.
Beginner: an easy project, minimal supplies. Pro: a more technical project that can (but doesn't have to) use more supplies.
A standalone library of core art techniques — perspective, chiaroscuro, color theory and more — each with its own step-by-step how-to guide you can practice on any subject.