A presentation in which you convince your audience to buy your design. Show them what you've made (with your maquette, pictures, a digital tour, a film or whatever you think is suitable) and how your audience is able to 'get one'. Persuade them into buying the design and make the audience believe that your deal is the best deal!
Check:
Digital presentation (Prezi, PowerPoint)
Is all the information in there?
Does it have a clear lay-out?
Does it look attractive?
Appearance
Do you look suitable for the occasion?
Do you have all materials you need at your fingertips?
Flyers
Do you have some extra copies to hand out?
Please, keep in mind:
Not to have a clicking pen in your hands. It's nearly irrisitible to start clicking while you're talking. Use a pencil or a marker instead.
Use a neat, clear lay-out, instead of weird-looking fonts, flashing images or sound effects in your presentation. They'll destract your audience and keep them from buying your amazing design!
Try not to feel too nervous. You have the best design and people will want it, as long as you are enthousiastic about it!