Cartography deals with the design of maps themselves. There are many good resources for improving your map design - among the best are:
Designing Better Maps: A Guide for GIS Users
by Cynthia A. Brewer ESRI Press, 2005, 220 pp - published by ESRI Press, this comprehensive book is a complete guide to a wide range of design techniques.
Making Maps : A Visual Guide to Map Design for GIS
by John Krygier and Denis Wood 2005 This book is equally useful, but focuses more on the concepts of design. It is less a technical cartography guide than a tour of effective map communication strategies. Purchase from Amazon.com
Other good web resources include:
North American Cartographic Information Society (NACIS)
Cartographic Communication Notes - Univ. Colorado faculty site, with an eclectic and useful array of guidelines
The Map Room - a great blog about mapping
Color Brewer and ColorBlender – useful tools for choosing colors that work well together in map design and cartography
Relief Shading website - for those who want to explore how to create beautiful elevation shading in their maps
Making Maps Easy to Read – A somewhat technical site in the UK that has a variety of good tutorials
ESRI Map Gallery – see this online gallery of users' maps
Communication Arts Magazine – go to Interactive Design Annual
Perry-Castenada Map Library at Univ. Texas - excellent online resource of a wide range of maps.
David Rumsey Map Collection, a remarkable online collection of over 10,000 maps from the 1700s to 1900s. –