Read on Twitter
After interviewing hundreds of founders at YC and now doing mock interviews, here is my most repeated advice. 4 questions investors are trying to answer: 
Question 1: What is it? If I don't know exactly what it is, it's hard to dig into it. Remove as much jargon to paint a picture in the head of someone who is *not* your customer.
Founders often describe their company as if the investor is a customer, which results in a lot of jargon.
Investors are not your customers.
Investors are not your customers.
Question 2: Will this team make a ton of progress in a short amount of time? If you are a solo founder, non-tech founder, working on it part time you will have to prove that you can make just as much progress with a team that is not solo, has tech and working on it full time
Progress is usually measured in revenue or active user growth. Oftentimes the solo or non-tech founders that are successful, they get a ton of progress in a short amount of time.
For teams that are early OR if you have a common idea (e.g. photo sharing), you will have lean into your unique insight and hence the team. Why you are the team to do it and no one else.
Question 3: Is there a problem and/or does anyone want your solution? How much traction or proof that there is a problem or people want your solution. Some of the best founders has signed up customers without writing a single line of code.
Question 4: How many people will have this problem or want your solution? In other words, how big is your market?
Investors are looking for companies that have multi-billion dollar markets. This is usually calculated by:
# of potential customers * avg annual amount each customer pays you = Total Addressable Market (TAM)
# of potential customers * avg annual amount each customer pays you = Total Addressable Market (TAM)
Most of the other questions "How does it work?", "How far along are you?", "How will you get users?", "What is unique about your solution?", "Why won't other competitors do what you are doing?"... etc.. are trying to figure out answers to one of the 4 questions above.
Good luck and please keep on building regardless of what happens. And, remember the more important opinion is that of your customers, not investors
