As you already say it is a matter of getting familiar with the system and how it works if you a book buying type then I would suggest The Debian System by Martin F. Kraft as a good purchase. For getting to know on your own I would suggest either subscribing to or reading through an email gateway like Gmame the debian-user, debian-devel mailing lists at
http://lists.debian.org. For must have packages I would install apt-listchanges and apt-listbugs to be able to read the changelogs and bug reports respectively you may also want apt-file if you do any compiling from source. Other than this just generally reading anything you can find in searches on problems you encounter is a good way to go. You may also want to search online or install the package rutebook to read on your machine the Rute User's Tutorial and Exposition.