One of the techniques I use is to practice. I always give my worst presentations in private. Rehearsing has given me the crucial feedback that my written notes/mind map would never give me and saved me from much public embarrassment, and saved the public from many a tedious, incoherent rambling.
Although rehearsing in private is hard work and feels artificial I have learned to value it as a private discipline. More times than not I would prefer to put the first rehearsal off. I find myself drawn to the graphics I will use and squander many an hour searching for that illusive 'right' image on the web.
On average I like to rehearse three times. It gives me a fluency of phrase, a confidence to be less dependent on my own notes/mind map, and helps me hear first the tempo and emphasis of what I have prepared.
Malcolm Gladwell in 'Outliers: the Story of Success' formulates a rough rule that it takes about 10,000 hours to master any complex skill, be it ice hockey, a musical instrument, or software development. Whether this figure is absolute for all skills or even true when it comes to public speacking, I don't know. But what I do know is that most of us only get a few crucial minutes in public to get our message across with clarity and impact. Private rehearsal is the only way I know of giving ourselves the mastery development time for this crucial influencing skill.
I'm speaking tomorrow, in fact, at the Best Practice User Group's Annual Members Conference in Milton Keynes. I'll be speaking on Programme Communications within MSP: Best Management Practice from Experience. If you see me there, please come and say 'hello.
P.S. I promise not to do 'Death by PowerPoint'. I'll be using Prezi.