A true expert is someone who can take a difficult subject and translate it so that those who are not experts can understand it. A metaphor is one of the best tools to utilize in a technical presentation to help position you as an expert in a topic whilst making the subject digestible to your audience.
Look around and see if you can identify any everyday items or activities that your subject can be compared to. Invariably most technical concepts are an engineering or programmatic way of reflecting a real world concept. If you can find something that parallels your technical topic that is understandable you will make your presentation understandable by everyone in your audience.
There is work involved in identifying an appropriate metaphor, but the reward will come at the conclusion of your presentation with an appreciative audience who will consider you the “guru” on your particular topic.