1. System flowcharts should read from top to bottom and from left to right. In drawing or reading such flowcharts, you should begin in the upper-left corner.
2. Because system flowcharting symbols are standardized, you should use these symbols when drawing your flowcharts—do not make up your own.
3. A processing symbol should always be found between an input symbol and an output symbol. This is called the sandwich rule.
4. Use on-page and off-page connectors to avoid crossed lines and cluttered flowcharts.
5. Sketch a flowchart before designing the final draft. Graphical documentation software tools (discussed shortly) make this job easier.
6. Add descriptions and comments in flowcharts to clarify processing elements. You can place these inside the processing symbols themselves, include them in annotation symbols attached to process or file symbols, or add them as separate notes on your system’s documentation.