At accelerators like Techstars, the "Office Hours" is a standard part of the program. A mentor comes in and a whole slate of companies are scheduled to meet with them for around 20 minutes or so. It's more than an elevator pitch, but not enough time for a full pitch. So what are you supposed to get accomplished in that time?
First of all, get it out of your head that Office Hours is time to pitch. In fact, any short meeting--an Office Hours or rushing the speaker after a speaking event, or an actual elevator ride--should never be thought of as a pitch. Your goal at these short meetings should either be to:
a) Seem interesting/smart/personable enough for me to want to meet you again.
b) To get a specific, thoughtful question answered that I might have a unique perspective on.
It should really just be a bridge to another meeting or interaction.
If you make it the kind of meeting where you rush through everything you're doing for me to just say "yes" or "no" to, you're missing out on all the other potential value you get get out of the meeting. You'd be abbreviating your pitch, missing out on the back and forth of a longer meeting where you can do a deeper dive, and probably not leaving enough time for me to get to know you. It's the worst possible time frame for an actual pitch.
Here's what I'd suggest instead:
1) First off, research beforehand. Know the types of investments I make, and if you can't figure that out, ask the leaders of your program. Don't waste your time getting me to talk about myself.
2) Spend the first three minutes saying exactly what you do. We can dive into that later. Basically, just describe to me what it might say on your landing page. "We're a human powered bookkeeping service... you just upload all your financial docs to us, scanned receipts, and we have an outsourced staff who will make sense of it and track it for a low monthly fee. We're aiming for the one billion small businesses out there who are too small to hire a CFO or comptroller." Bam, done, I get it. We can do a deeper dive later to understand the inner workings of that, but now I get what you do and that you're going after a big market.
3) Why you? Do you have a killer team of coders, or are you the sales guru? What is it specifically that makes you the right team for this problem. This is not for you to describe your resume back from elementary school. It's a way to tell me, "I led the team who built eBay Motors--I can sell cars online."
4) Explain to me what you're aiming to accomplish over the course of the program--why are you here--that's another 3-5 minutes.
5) Right around midway, let me know what you think I can be helpful with--besides money. I don't invest in anything where I'm just money. I want to be able to help the company in some way. Do you need introductions to customers, feedback on the customer messaging, or perhaps insight into who may have tried something like this before?
6) Spend the rest of the time on next steps--is there a specific list of people that I think you should talk to?
7) Follow up!! Send me a freshly composed note saying, "Hey, thank you for meeting, we'd love to follow up with the people you mentioned today. As a refresher, here's three bullets about what it is that we do." Then send me another e-mail with a reminder of the 6 people I said I'd send you to.
8) Kill it with those intros. Your goal is for me to hear back from the people I sent you to thanking me for the intro, because you were so smart/awesome, helpful, or solved a pressing problem they had.
And that's how you make the most of 20 minutes.