I see a lot of startups overshoot the mark on this - and instead of producing FOMO and excitement - they produce rolling eyeballs by overstating their market or making claims of capturing specific %s of a market before they've captured their first customer.
It is key to have figures that are believable and relevant to your specific market. If you are going to manufacture a steering wheel cover, don't talk to me about the $1.6 Trillion dollar auto industry.
The more specific you can be - the more myopic your focus on your niche within a market - the better. It shows that you understand your market well - and that you're not trying to entice using the unattainable.
The market size is a necessary metric - but from a "convincing" standpoint - my attention is far more often grabbed when I see that a founder understands things down to a unit level - how they will acquire their first customer, what that acquisition will cost - how much they will pay for the product / service - how much delivering that product or service will cost. That along with a credible and clear market size will allow investors to clearly envision the potential.
You need to get some real life stories on how your product or service would solve a problem. Thats first and foremost.
- then statistics and survey experiments confirming the pilot
- the solutions you tried and failed
- eureka on what has worked so far
- what did you learn and what changes do you want to make
- where do you stand now & where do you want to go from here
- who is with you / against you
- what do you need: for what - what will you earn - who will pay / or how we will get money
- how is the customer's life going to be different when you succeed
- and finally what's the exit plan for the VC