One of the simplest guidelines to follow is leveraging AWS PaaS services wherever possible to enjoy the benefits of scalability and availability out of the box, without the associated administrative headaches or design complexity. Don’t reinvent the wheel when ready-to-use services such as email, queuing, search, databases, monitoring, metrics, logging, and so on, are available to you from Amazon or other third-party vendors. For example, you can leverage the RDS or the DynamoDB services available for scalable relational and NoSQL database services, respectively. Similarly, you can leverage the AWS SQS service, as it offers a multi-AZ, scalability (unlimited messages), and a secure queuing service accessible via simple APIs without having to roll out your own implementation or managing an open-source product deployed on an EC2 cluster. 

There are several standardized and highly scalable monitoring, metrics, and logging services available—use them. Additionally, look for opportunities to get rid of server-based computing and use AWS Lambda instead. Lambda can be used to implement event-driven computing functionalities using languages such as JavaScript, Java, and Python.