
The Wall Street Journal Guide to Information Graphics should be a required for reading for anyone working with numbers.
tldr: only use color when necessary, avoid bold typefaces, keep scales consistent across charts unless there is a specific need to do otherwise.
The Wall Street Journal Guide to Information Graphics is an essential reading for anyone who regularly presents data.
I am a big advocate or arranging the pie slices in order (largest to smallest, or smallest to largest).
I also really recommend The Wall Street Journal Guide to Information Graphics: The Dos and Don'ts of Presenting Data, Facts, and Figures https://www.amazon.com/Street-Journal-Guide-Information-Grap...
But for your situation, check out some of these sites which focus on more complicated graphing techniques:
http://www.perceptualedge.com/examples.php
http://blogof.francescomugnai.com/2009/04/50-great-examples-...
http://interface.fh-potsdam.de/infodesignpatterns/news.php
http://webdesignledger.com/inspiration/15-stunning-examples-...