My VPS hosting company said my database is very big and it should be optimized. Can anyone point me in the direction on how to optimize a full database?
It often happens that WP plugins pump the database full of logs that should be purged periodically.
Pending comments, post/page revisions, stored contact form submissions etc can also make your database larger than it should be.
Also if you had plugin in the past that you no longer use, their data might still be in the db even though the plugin itself is no longer on your site. The database can still contain orphan tables etc.
Super Important: BACKUP BEFORE any kind of playing around with databases of any kind! Also, check with your hosting if they have an automatic daily backup or similar.