To get started in your efforts to involve the audience I recommend that you take a big axe with you to each one of your presentations and chop the lectern into tiny little pieces. That way you won't be tempted to stand behind it. The behind-the lectern speaker is quickly going the way of the dinosaur.
Make every attempt possible to avoid delivering your information from behind a lectern (unless protocol and/or logistics absolutely demand that you do). To be most effective, you want to eliminate any barriers between you and the audience. If they can see you, and if you are physically close to them, they will have a greater rapport with you. They will be able to notice your facial expressions and body language much better than if you have a physical barrier in between. A friend of mine who is a top-notch humorist was asked to do his presentation in a room that had a dance floor between him and the audience.
Needless to say the presentation suffered immensely.
There are many more things to consider for better presentations.