A lot what separates good and bad cooking is tacit understanding that can't be explained in words. You need to practice to detect the nuances in flavor. It's really basic and doesn't make good edutaninment content.

I'd say 90% of being a competent chef is just down to knowing how to balance the basic flavor components; and to figure out how these things change during the cooking process.

With practice and experimentation you can learn to infer what is lacking by taste and make anything go from bland to amazing.

Spices and ingredients are much less important. They aren't unimportant, but they aren't what makes something decent into something great. You can make a head cabbage more delicious than most what you'll find in a cookbook if you get this right.