Some of the best practices if PaaS is the preferred deployment model are listed here:

• Choose the appropriate Azure SQL tier (whether basic, standard, premium RS, or premium) and appropriate performance levels in terms of DTUs.
• Choose appropriately between single databases and elastic databases. If there are a lot of databases, it is more cost-efficient to use elastic databases compared to single databases.
• Ensure Azure SQL security  - encrypt data at rest and in motion, data masking, threat protection are enabled.
• Ensure that backup strategy and data replication is set up according to business demands.
• Ensure there is redundancy for web apps with multi-region availability using traffic manager
• Use Redis cache and CDN for faster delivery of data and pages.

• Re-architect your solutions to use PaaS solutions (such as serverless solutions and microservices in containers) rather than Infrastructure as a Service (IaaS) solutions. These PaaS solutions remove maintenance costs and are available on the consumption-per-minute basis. If you do not consume these services, there is no cost, even though your code and services will still be available round the clock.