Why is it important?
Complex ideas need to be communicated to your audience as clearly as possible, so they can understand your thinking without any difficulty or distortion. This involves thinking about what they need to know, the best way to get that across, and how ideas are structured.
How do I do it?
Presentations are about you as the presenter, as much as anything you put on screen. You need to make a connection with your audience through eye contact, open body language and a friendly tone.