What makes Mark Bradford's work work?
Zoom in to the micro level, and it is just shapes; tones, colours, edges - anyone can do this and they could be made from anything; pencil, paint, photographs - it almost doesn't matter when your viewing it as a whole piece.
Where the piece comes from, how the piece works is by carefully considered and executed contrast.
Contrast is simply difference.
Difference in complexity.
Difference in colour temperature.
Difference in smooth or rough.
Difference in straight or curved.
Difference in crowded or sparse.
This list can go on and on...
What you are ultimately communicating in a pictorial artwork as the eye moves across it is 'this area is different to this, this area is now warmer, this is an edge, this is soft and blended'.
In this way it does not matter which medium it is in - these rules are universal. So all an artist really needs is a good eye.
A good eye for what they are observing, which could be a physical object or an intangible idea - and then the ability to compose visual contrast in a way that elicits an effect.
There are the details, the minutiae and implementation, of how exactly you achieve these effects within a medium - but these are mostly understood through curiosity and experimentation and failure - they happen naturally over time and with targeted practice.
Understanding that it is all about visual contrast allows artists in any medium to operate on a higher level, one that transcends the medium and can be continually worked on... there are no more failed experiments, just things that went wrong that you learnt from, there are no more 'bad mediums' there are just ones that didn't give you what you needed.
As long as you understand the why of those failures.
They are all meaningful lessons towards understanding and observing and controlling visual contrast.