The document provides 10 tips for optimizing SQL. The tips include: selecting only necessary fields; updating in batches; using left joins; defining constraints like unique and foreign keys; deleting in cascades; ensuring optimal index sizes; using indices; analyzing and explaining queries; using SQL optimization gems for Rails like Bullet and lol_dba; and leveraging features like HSTORE, JSON, and concurrent indices. The tips are part of a longer discussion on SQL optimization by Bruno Andrade on January 14, 2016.