Identify the system or process to be modeled
Define the scope and boundaries of the diagram
List all external entities that interact with the system
Identify all major processes within the system
Identify all data stores used by the system
Determine the data flows between entities, processes, and data stores
Draw the context diagram with the system as a single process
Add external entities around the system boundary
Connect external entities to the system with labeled data flows
Expand the context diagram into a Level 0 DFD
Break the system into major subprocesses
Connect subprocesses with data flows
Connect subprocesses to data stores and external entities
Ensure each process has at least one input and one output
Balance data flows between levels of the DFD
Use consistent symbols for processes, data stores, external entities, and data flows
Label every process, data store, and data flow clearly
Check for missing, duplicate, or invalid data flows
Review the diagram for clarity and completeness
Refine the diagram as needed
Validate the diagram with stakeholders