Doing a lot of presentation? Make it a CRAP.
Text and images are all the same size and style is extremely boring and not communicative. Add some contrast to make it interesting.
Repeat colors, fonts and images throughout your presentation for a cohesive feel (remember color mix?). Each new topic slide should have related styles so that your audience knows you are moving into a new point.
Text and alignment on each side should be visually connected. Nothing should be out of place.
Related elements should be grouped together.