If you are creating a map, either by using a Geographical Information System (GIS) such as ArcGIS, or another method, such as Adobe Illustrator, it's important to think about what your finished map looks like. You can create a map easily using GIS, but the default values are not necessarily going to give you an attractive and usable map.
There are a number of resources available to help you, both in print and online.
Making Maps: a visual guide to map design for GIS. Third Edition by 
GIS Cartography : a guide to effective map design. 2nd ed. by 
Web Cartography : map design for interactive and mobile devices by 
Thematic Cartography and Geographic Visualization. 2nd ed. by 
Cartography: a compendium of design thinking for mapmakers by 
Cartography: an introduction, 2nd ed. by 
How to make maps: an introduction to theory and practice of cartography by 
How to Lie with Maps by 
Routledge Handbook of Mapping and Cartography by 
Designing Better Maps. 2nd ed. by These days we are more likely to use maps online - on a mobile or tablet, or as a print out, than as a folded printed map. Some might say that this way they only get the bit of the map they're interested in; others would say that the larger map gives them more context, so as to understand the bigger picture. In the past, when a printed map was the only option, the covers became very important - like a book, they gave a clue to the content. They would have pictures of hikers, cyclists or motorists enjoying the countryside, usually with an open map in front of them. Older maps are now often collected as much for the covers as for the map itself. Below are some links to works and web pages about map covers.
Map cover art: a pictorial history of Ordnance Survey cover illustrations by