The foundations of a successful system design are clear processes, consistent approaches, and the use of an architecture development methodology. Key choices around the software to use, whether to extend with SDKs, or environment isolation are all key decision points.
Beyond technology, the people that support and operate a deployment are the most important ingredient to success. Organizational processes need to be developed to operate GIS systems at scale and with efficient resource utilization.
Create clear and consistent diagrams for ArcGIS-based systems using diagramming toolkits and guidelines, including iconography, styles and helpful resources. Instructions are available for Visio, Lucidchart and draw.io.