Secrets in photography, by Mark Blezard
Okay, an impossible ask but here are five of the more important ones:
Light. Quite possibly the most important thing to understand when you start out in photography. Consider this, photography is 'painting with light'.
Exposure. Again, the 'painting with light' thing. How much light and where. Learn what your light meter is doing when you pan an image. Consider how it changes and why.
Focus. No, I don't just mean 'sharp', but understanding the effective use of 'depth of field'. Learn your aperture settings and their results. The smaller the aperture (f18, f22, etc.) the more of your image remains in focus. More dramatic, the wider aperture settings will allow you to pinpoint your subject with dramatic results. Don't just use AF!
Composition & Perspective. Composition will make or break your images. And for perspective, go take a look at Salvador Dali's paintings to learn more. Look at your old images and try and identify where your eye finishes – not starts.
Equipment. Got the above? Now it is time to expand upon these points with the right, more flexible, equipment. And not before! If you want to be a top racing driver the best way to learn is in a slow car. You learn the racing lines, because without this most basic skill you will never win. The same applies in photography, if you can get great images from a simple camera you will be able to make use of an expensive one. But not before.
And finally, a bonus tip. Never consider yourself an expert. Light is infinite and so, therefore, it is your infinite learning experience!