I've been to quite a few writing conferences this year now, and since this question has come up a couple of times, I figured I'd take the time to answer it.
With more and more conferences switching to virtual settings, Zoom Breakout Rooms with built-in timers seem to be the default for pitch rooms where authors have a set amount of time (6-10 minutes, usually) to pitch an agent of their choosing. I've posted before about the things I like in a query, but if you've perfected your query letter, you might want to use that as a basis to talk about your characters and plot lines in your pitch.
I don't want to get too bogged down in non-fiction, since I'm not actively growing my client list on that front, but If you're pitching non-fiction, then you need to have a real understanding of the story you're going to tell and why you're the one to tell it. Give the agent you're pitching a reason to know that you're the best person to tell this story.
If you want to ignore the rest of this blog post, then just pay attention to this one paragraph:
For me, when I'm taking genre fiction pitches, I want to know who your characters are and what their failures are going to be: where they're going to struggle, why they're flawed, who they love, who they hate, etc. Characters are the most important part to me, personally, because if you can show me that you've done the work in creating complex characters I care about, then you can stick them wherever you want--on a desert planet, in a western setting, on an island in the middle of the ocean.
Now let's talk about pitches in general, because beyond what I mentioned above, I truly don't expect much from a pitch. I want a quick synopsis and understanding of your world, sure, but I want to engage with you on your text. Tell me something that's curious or interesting so we can talk about it.
Why don't I expect much? Because, and here's the honest truth for fiction authors pitching agents: no matter what you say, the proof is in your writing.
I've been pitched stories that sounded incredible, and others where I was maybe on the fence. Some of those pitches have had great writing behind them, others, not so much. I'm not going to sign you as a client based on your ability to pitch your work. I'm going to do it based on the words you put on the page.
That's not to say your pitch doesn't matter. If you have a pitch session that doesn't go well, then the agent may tell you not to submit to them. But almost every agent has a story of saying "I don't want story about X," then they get the one story that breaks all their misconceptions and they run with it anyways. If you can write your story then do it. Spend the time on your query letter and make sure the writing there is as perfect as your story is. Go be the best at what you've written.
So if you had a bad pitch, trust me, that's not the end of the world. In fact, it could still be the start of your journey.