Who cares if your family and friends love it--your audience wants to know if there are thousands of potential buyers for your idea. You can really shine in a presentation if you've done your market research. Show the listeners competing products, then explain why your idea is better. Have independent market research done on your idea, and share the results. And get experts in the market to evaluate your idea. The more market research you do, the fewer excuses listeners will have to turn down your idea.
You should also present documentation regarding the potential market size. If your idea is a daily planner for moms, for example, saying the market is 50 mil-lion strong because that's how many mothers there are in the United States is weak because that figure is too general. Pointing out that 7 million mothers have children between the ages of 5 and 15 makes a stronger case.