I am of the belief that the majority of people can improve their presentations dramatically by focusing on eliminating bad habits and presentation skills more than seeking to add anything on. How often have you come out of a seminar and overheard someone say, "Wow, she was great! Did you see how effectively she used her hand gestures?"

That said, here are some ideas to help you become a better speaker. 

1. Keep it simple
     Speak naturally
     Make eye contact
     Don't do crazy things with your hands
     Don't do much more than speak, i.e. managing props etc.

2. Be impassioned 

3. Balance the format of your information

4. Build the relationships beforehand if possible

5. Get the audience to participate at varying levels if effective

6. Show, don't tell. That is, use stories, not facts and figures

7. Get rid of distracting idiosyncrasies

8. Don't misinterpret people's actions and get discouraged

9. Know your material