https://blog.hubspot.com/marketing/inspiring-slideshare-presentations-for-marketers-list
Some good tips from the folks at hubspot:
1) Less is more.
2) Keep text to a minimum.
3) Rethink visuals.
4) Incorporate multimedia.
Bonus: 24 Great SlideShare & PowerPoint Presentation Examples for Marketers
How to Produce Better Content Ideas from Mark Johnstone