Here are some best practices to follow when backing up your Azure VMs;

Agentless VM backup: Complete image backup of the Azure VMs, including the operating system, applications, and data and store the backups in On-premise or Cloud.
Incremental backup: Only the changes made since the last backup are backed up.
Application-consistent backup: Ensures application-consistent backups by leveraging Microsoft’s VSS (Volume Shadow Copy Service) technology.
Automated Snapshots: Create automated snaphots for Azure VMs and launch them as VMs or restore only specific volumes.