Make sure you maintain a consistent graphical language throughout your slides. Here is a thumbnail view of a section of a deck I used in recent meetings.

Here are the guidelines I used:

• Dark background, white text, purple accent

• Page-filling, black and white images

• No capitals

• Selectively bolding a word in a sentence

• No slide titles in a fixed position

Every slide blends right in without, complicated graphics, and SlideMagic makes it really easy to apply this style.