One of the things I recently learned from James Whittaker (http://www.docjamesw.com/) is to try and tell a story. Previously I thought I had done a pretty good job about avoiding the wall-of-text type slides and doing more talking via memory and improvisation. While I felt that was ok, I think the idea of being able to work an actual story around your talk helps a lot with keeping your audience engaged.

I realize it's hard to do that for some types of talks but it's something I have been working on this year.