Mastering contrast, color, sharpness, and clarity
Contrast, or more specifically, the lack of contrast, is often the most noticeable fault in many pictures. This is partly because cameras are designed to capture images in a slightly lower contrast than we perhaps remember—and in doing so, they capture a slightly wider range of tones than if they were recording higher contrast from the get-go.
I equate this effect with the difference between professional film and film bought over the counter in a supermarket. The supermarket products always looked superficially really good because they were super-colorful and quite contrasty. But they were no good for commercial photographers because they would not be able to record valuable detail in the sensitive highlights—such as a white wedding dress.
Professional film is typically low-contrast and captures a wider range of tones for which the contrast could be increased if and when needed. JPEGs, and specifically RAW files...