One of the key challenges of being a speaker today is that people are suffering from information overload, especially if they're attending your presentation virtually. They have a lot of content that they're already consuming on the Web, through their mobile devices, television, social media, etc. They're being bombarded with a lot of information, and they've become very savvy. They've heard a lot of good speakers and they can easily detect speakers who are not sincere.
You have to sincerely engage the audience so you can break through their distractions and capture their attention.
You also have to tailor your message to that particular audience so your content is seen as relevant, relatable and valuable. For example, I usually talk to several people from the audience well in advance of my speech so I can understand their day-to-day work and make sure my program is meaningful in that context. (Thanks to Alan Weiss, author of Million Dollar Speaking and 40+ other books, for introducing me to this idea - www.alanweiss.com)
The next time that you have to speak in front of an audience, remember that your challenge is to break through the walls of "I've already heard this," and "I have a million other things to do so why should I listen to you?"