Documentation and tools.
Real Documentation exists. Online and in print. The reading of several of these is required to make the step from small time DNS admin to a big time one. In print the standard book is DNS and BIND by C. Liu and P. Albitz from O'Reilly & Associates, Sebastopol, CA, ISBN 0-937175-82-X. I read this, it's excellent. There is also a section in on DNS in TCP/IP Network Administration, by Craig Hunt from O'Reilly..., ISBN 0-937175-82-X. Another must for Good DNS administration (or good anything for that matter) is Zen and the Art of Motorcycle Maintenance by Robert M. Prisig :-) Available as ISBN 0688052304 and others.
Online you will find stuff on http://www.dns.net/dnsrd/, http://www.isc.org/bind.html; A FAQ, a reference manual (BOG; Bind Operations Guide) as well as papers and protocol definitions and DNS hacks (these, and most, if not all, of the rfcs mentioned below, are also contained in the bind distribution). I have not read most of these, but then I'm not a big-time DNS admin either. Arnt Gulbrandsen on the other hand has read BOG and he's ecstatic about it :-). The newsgroup comp.protocols.tcp-ip.domains is about DNS. In addition there are a number of RFCs about DNS, the most important are probably these:
A. Gulbrandsen, P. Vixie, A DNS RR for specifying the location of services (DNS SRV), October 1996
Y. Rekhter, R. Moskowitz, D. Karrenberg, G. de Groot, E. Lear, Address Allocation for Private Internets, 02/29/1996.
D. Barr, Common DNS Operational and Configuration Errors, 02/28/1996.
B. Barr Errors in RFC 1912, this is available at http://www.cis.ohio-state.edu/~barr/rfc1912-errors.html
A. Romao, Tools for DNS debugging, 11/03/1994.
C. Farrell, M. Schulze, S. Pleitner, D. Baldoni, DNS Encoding of Geographical Location, 11/01/1994.
R. Ullmann, P. Mockapetris, L. Mamakos, C. Everhart, New DNS RR Definitions, 10/08/1990.
P. Mockapetris, Domain names - implementation and specification, 11/01/1987.
P. Mockapetris, Domain names - concepts and facilities, 11/01/1987.
M. Lottor, Domain administrators operations guide, 11/01/1987.
M. Stahl, Domain administrators guide, 11/01/1987.
C. Partridge, Mail routing and the domain system, 01/01/1986.