1. Absolutely do not ever under any circumstances load your slides with text and then proceed to read it to your audience. Your audience can digest information more quickly internally than you can read it aloud. If you do this it will lead to bored faces and audible yawns.
2. Pictures, images, graphs, infographics work better than text most of the time.
3. Do not try to dazzle me with 2,000,000,000 different slide transitions, fonts, and formats. Uniformity is best. And, on that note - less is more!
4. If you are not interested your audience won't be interested. Also, if you are not interested why are you presenting on this topic? Life's too short to do work that isn't interesting (at least most of the time).
5. Prepare in advance as much as possible. Get into the presentation room early and set up the tables and chairs how you would like them. Set your computer up, test the data projector and audio. Physically click through all of your slides at least once in advance of the audience arriving to make sure there is no lag and it looks as good on the big screen as it does on the small screen. Furthermore, make sure you can read the text comfortably from the position of the farthermost audience member (nothing worse than someone straining to see!). Make sure any audio is volume adjusted for size/ambiance of room.
6. Make sure you are comfortable with the material. That goes further than just knowing what's on the next slide. Do you know enough about this topic to field questions properly? If not, consider spending more time preparing before getting up.
Interested to hear some other opinions on this...