To complement the rest of the answers, this one with a focus on ‘how’ in practice pitch investors:
Scroll down till the end for links (downloadable) and get a template from Sequoia Capital and the AirBnB’s epic pitch deck.
Now, some recommendations from Silicon Valley’s trenches:
The best companies in the world are financed by their customers. While this is the ideal state for any venture, external financing may be necessary along the way. At that moment is when the Pitch Deck becomes your weapon of choice.
These are the key messages to convey to investors and trigger their interest, and their funding, for your project:
Focus on the need (the problem you are solving). Clearly articulate your solution. Sometimes a crisp and thorough explanation of the problem to be solved is more important than the solution we are trying to sell as it may change or pivot.
Metrics: How big is this thing? Market size, audiences, where are they? How badly do they need this? If your have no revenue, where is the evidence for this need? have you piloted it? Reference points can be built quickly out of readily available online tools like Kickstarter, Survey Sampling, Data Collection & Market Research Solutions, SurveyMonkey Google Trends and Adwords to show proof of market demand. This is also referred to as market validation.
Demo your solution as much as you possibly can. If an image is worth a thousand words, a real-life demo is worth 10 thousand at least.
Competition: Who are they? What is it that you have and they don’t? What is the plan to outsmart them? Typically, for new tech products or services, it is very much about adoption speed, critical mass, user engagement versus distribution, as opposed to focus on branding or financial muscle on a bigger scale. But you may have a new a fresh approach. Just make it clear and sound.