A very useful introduction to composition from the talented Sumeet Moghe.
This one is about gear.. Cameras, lenses, understanding focal length, tripods and other accessories.
This one is about exposure. It's a fundamental one that I recommend to students who wants to go beyond using their camera on automatic and learning to get the most out of photography.
This one is about Elements and Principles of Design in Photography. Also very useful.
This one I recommend for anyone who has attended or is about to attend my Introduction to Lightroom or Intermediate Lightroom workshops.