You're in luck! :)

Error handling, error handling, error handling. In particular, use {RaiseError = 1} when you're connecting to the database to tell DBI to check and report errors for you. That alone can save lots of grief.

You can refactor some of the database calls, by preparing them once, then binding/executing when you need to invoke them. See (Ovid) Re: DBI placeholders for hints.