Auto-Create FTP & MySQL Accounts for clients
When creating new client accounts in cPanel / WHM it automatically creates a main FTP account as well as a MySQL account for that user. It's really not much extra work to go manually add an FTP account onto a clients account but it seems like an added step that should be pretty quick to fix.
A default MySQL user allowed to access all databases on that users account would be nice too. Personally i tend to forget the randomly generated passwords once they're entered into their corresponding config files.