Presenting is an art, some people are good at it, some are not, everyone could do with a little improvement.
I've believed for a long time that you should be able to describe your topic verbally, or with pen and paper, before anyone lets you loose with a multimedia presentation.
Lately, when provided with a presentation to deliver,(using either Notes 8 or OpenOffice), I have taken to removing slides with too much content or without a simple graphic. Really keep it simple.
The video below is a classic, funny sketch that is well worth watching.