The better you understand how your camera's and lenses work, the more effectively you can use them.
The strength of an image flows largely from the strength of it's composition, it's composition that tells the story without words. Design, thinking though the placement of elements in the final image, is a major part of building a strong composition.
Gone is the traditional darkroom, film, and chemicals; in it's place is software and computers.
Purpose built photo-gear is expensive, but with a little time and ingenuity you can build functionally equivalent solutions in your home or studio.
Photography is about light. Learn how to bend it to your will.
There's always a better way to do things, when I find them I'll share them here.
The study of behavior, and to some degree biology, are necessary aids for wildlife photography.