Don't SELECT * unless you really need all columns (1)

Update Only What Needs Updating

Disable Constraints and Indexes During Bulk Loads

Use UNLOGGED Tables for Intermediate Data

Implement Complete Processes Using WITH and RETURNING

Avoid Indexes on Columns With Low Selectivity

Use Partial Indexes

Always Load Sorted Data

Index Columns With High Correlation Using BRIN

Make Indexes "Invisible"

Don't Schedule Long Running Processes at Round Hours

Consider using a timestamp instead of a boolean (2)

Enclose comments (e.g. use /* comment */ instead of -- comment) (3)

Consider SmartDB/PinkDB.. especially for cloud, especially for chatty apps

Use as few engine-specific hints as possible in your queries (4)