Hmm..since I am a bit experienced i wouldn't
say that you would get very far by just
reading on *nix systems.
My personal tip:
-Read about *nix systems (yes, read)
-Practice a lot, start out with::
-Read about the internet,(not some dummy book like; Internet for dummies) go for the real books with the real information, like; Administrators guide to setting up servers, Administrating networks, and such books...
-Learn a programming language, and learn it good! Prefered for *nix systems would be C, but since I still go to school, I have chosen C++ (thus I can get a work in the future).
-If you go to a college or higher education, take computer security classes.
Well this is just a little piece of the whole pie.