There seems to be a natural wall between the speaker and his or her audience when a presentation first gets rolling. A wall of caution and restraint that can dampen that initial engagement. The people you are speaking to are silently asking themselves, “Who is this person? Are they credible? Or are they just full of it?”
A wonderful way to breach that wall before you even take the stage is to “work the crowd.” Arrive early, spend a little face time with as many folk as you can. Introduce yourself and your topic. Tell them how excited you are to be speaking to them today. This is especially powerful with small and medium size crowds.
Then when you take to the podium you have a room full of friends ready to absorb your very first words. And you are warmed up as well.