The Theory of Constraints (TOC) is an important optimising technique that focuses on improving the throughput of work. This is at the (usually) single bottleneck or constraint in the workflow.
There is usually very few, and often just one, thing that causes a logjam in your business.
This is true of many types of business; not just manufacturers of products.
TOC needs to become an ingrained habit. So that you are always looking for the opportunities to dramatically improve your businesses throughput.
Theory of Constraints (TOC) can be applied to all business types. Retail, manufacturing, service.
Combine TOC with the 80/20 Principle and watch your business grow.