Getting other people excited about our ideas is all about preparation and knowing the audience. First, consider preparation. Do all your advance research. Has this worked in other places? Can you cite authorities or statistics that back your idea? What are the available resources of time, money, people, etc.? Think in terms of results.
What will happen if your idea is accepted? What will happen if it won't? Who do you need on your side as an advocate for your idea? Tell them your idea and get their feedback so that they have no problem supporting you. Now, analyze the audience. Is your idea best received as a report? Presented live at a meeting? Brought up in casual conversation? When is the optimum time to present your idea? In other words, when is a prime time to get their attention? Know what your audience values and present your idea in terms of benefits that they value. Don't get bogged down into too much detail. Have detail in hand and be ready to anticipate objections and questions. But first, paint the picture.