If you are building out a webapp or enterprise application what would a standard architectural diagram for this look like?
There's no standard diagram for building services on AWS. Instead, there are reference architectures and proven patterns based on the customer's needs. It could be as simple as using S3, CloudFront, and API calls to DynamoDB, or as complex as creating an analytics web app with Flink in the background.
When starting to build a new service, my first suggestion is to apply the AWS Well-Architected framework. This helps address all the important aspects of the system. After that, check if there are common design patterns or AWS reference architectures that can be used to streamline a significant portion of the case and then build upon it.
Lastly, simulate the costs using the AWS Pricing Calculator with your initial architecture draft. This step helps ensure you can afford all the requirements for the service, and the questions asked during the simulation can prompt you to identify any potential challenges or adjustments needed.