Usually, I still fail to do this 100%: setting the personality of a presentation and using it consistently throughout the slides. What contributes to a presentation personality:
Let's think of a few possible presentation personalities:
- The basics: colors and fonts
- Slide design approach: huge images/few words, "Economist-style" data diagrams (headline message supported by a graph), bullets (uh oh), cartoon-style, etc.
- Type of images: color or B&W, "tacky" stock images or real pictures, people or landscapes/buildings or isolated objects, funny or serious, vintage or recent, images-only or illustration-only, etc.
- Vintage 1950s images (family scenes, food advertising, first electrical appliances)
- College humor (brutal, in-your-face, "funny" stock images isolated on white)
- Zen (few colors, calm images, Helvetica light font)
- Feminine (paintings, elegant images, some frivolous elements)
- Economist (clean/neat data charts, one after another)
- Cartoon (hand drawings, cartoon-type fonts, including very fat ones ["BANG"])
- Napkin-style (simplistic drawings, hand-written/white-board style comments on printed text)
- Macho (black background, performance cars)
- Big words on a white background
- Big words on a colorful background (Tom Peters)
- Anti-design presentation (see Dave McClure's work, I am only discussing his presentation personality, not his real one...)
Related reading a post by Olivia Mitchell on The top 7 PowerPoint slide designs.