Productivity blog Lifehack.org has come up with an intriguing way to get rid of those awkward um's and ah's we are all susceptible to when speaking in public: punctuation codes.
Make a note whenever you are doing a presentation that every comma you encounter should have a pause attached...The end of a sentence requires twice as much pause. There is a time-delay between hearing your words and registering their meaning. Don`t cut over this step by blurring together your sentences...Underline key words and phrases and double underline especially important ones. It helps you understand where to slow down and emphasise an individual word.
This is a super easy idea to implement, and could really up the quality of your presentation.