Guy and Eitan list several common mistakes done by DBAs in SQL Server.
Some relevant links:
- Architecting Database Dev and Test Environments: Best Practices and Anti-Patterns for SQL Server
- Ola Hallengren's Maintenance Solution
- HADR My Jobs - Open Source Solution by Madeira
- Columnstore Indexes: Planning and Implementation
- TSQL Script to Check for Weak Passwords
- Script to Check for Max DOP Configuration Best Practice
