A great book is Cynthia Brewer's Designing Better Maps. This will give you some ideas about visual hierarchy (making some elements appear more important than others), and how to use color, texture and pattern to your advantage. IIRC there's a section on font and typeface as well. Additionally, Ms. Brewer has a great online resource called ColorBrewer2.0 that is helpful in determining color combinations and includes criteria such as colorblind-safe, use in print or multimedia.
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These are where I would start and I believe many undergrad cartography courses would start too. Good luck!
I always enjoyed this book, I received it at a conference around 2007: