Make sure you answer the basic questions that listeners will want to hear. Present a working prototype. Show off the uniqueness of your project by presenting a working model. The quality of your model speaks volumes about you and your product. Get your idea patented.
Companies generally seek ideas that are patentable.
If you have not obtained a patent for your idea, get a confidentiality agreement signed before you discuss your idea. Do your market research. Your audience will be impressed by your efforts to analyze market trends and solicit expert opinions. Know the manufacturing costs of your idea, along with other relevant information. Be professional under all circumstances.