- Use unsigned numeric integers (properly scaled for the size of your tables) without leading zeros.

- Start out with third normal form (3NF). Use associative tables to eliminate redundancy at first.

- Avoid storing files in the database. Use numeric filenames to associate data records with the file system.

- If necessary, use table caching and views to optimize performance based on use patterns. This should be done in conjunction with software app testing.

- If you need to shorten URIs passed between APIs or URLs for the user, make a relationship table referencing the longer URI with a shorter handle. Use numeric handles for small data sets or alpha numeric for larger data sets.

- For time related queries, associate the numeric primary key of long tables with relevant timestamps (hourly, daily, weekly, monthly or  other time intervals that your social web application would query.) This will reduce query time for long tables.