Most manufacturers have good chemicals and while people have personal preferences. Each person needs to work with the chemicals they have to understand how they work best on the types of materials, soils and stains you clean frequently.
The principles of cleaning and getting good results are:
Vacuum soil
Identify the material/fabric you are working with
Identify the type of soiling
Use a pre-spray for the appropriate soiling ? grease, food, etc ? remember dwell times to allow chemicals to work
Use an enzyme if you have an odor
Use an appropriate stain remover if you have a stain ? generally blotting up the stain
Agitate the fibers ?to loosen soil and bring to surface
If still heavily soiled re apply pre-spray, agitate blot and transfer soiling to cloth
Extract to remove soiling ? with extraction machine ? better success comes with hot water and from a machine with a good vacuum lift and minimal over-wetting of fibers
Rinse
Dry rapidly
The idea behind the pictures is to demonstrate to people, that it is possible to clean very well, you just have to push the envelope on cleaning all the time to increase results.