As far as slides are concerned, there are two different (although closely connected) fields you can draw upon: graphic design and information visualization. Both fields are on the rise, with new names, books, blogs, and concepts popping up all the time. Unlike storytelling, which is all about structure and deeper meanings, design is visible; it's inherently outward-oriented. You can see it.
I was totally blown away Robin Williams' The Non-Designer's Design Book. This book really changed my life. Read it. The three principles formulated in this book largely came from several design principles Williams formulates. This book changes your everyday perception of things. Suddenly, you can tell good visual communication from bad visual communication.
As far as visualization methods are concerned, after reviewing a number of books, I am still convinced that the best book for beginners is Gene Zelazny's Say It With Charts: The Executive's Guide to Visual Communication. The book is quite old, so the word “executive” could be safely ignored. Now it is a guide for everyone. When I was researching material, I re-read it from cover to cover, and it is still an ...