Photography and Film
Digital Photography School – A great all-around site for tips on technical and artistic aspects of photography, as well as reviews and advice on equipment, and more. For tips on composition, click here.
National Geographic Photo Tips – Does this need explaining?
Design
Tips for Effective Visual Communication – Tips from the graphic design world
Data Visualization:
Why Most People’s Charts and Graphs Look Like Crap
Getting Data Visualization Right
Until the Lions 