• High level description of market need and how the product addresses that need (an evangelist's pitch that is hopefully in your story already)
• Market size – this has to be bottoms up. Not "American companies spend $6 gadzillion per year on software. We address 15% of that market." Instead, "There are 2.5 million logical potential customers in our market. Our product will cost $2,000/year/customer. That makes for a $5 billion Total Addressable Market." Beyond that, do anything you can to offer insight on how that market is segmented and which segments are most attractive.
• Business model / unit economics – how does your business actually make money at the level of an individual sale/customer? Price – COGS = gross profit. Then what's the sales/customer acquisition model? You need to really understand this in a detailed way so that the investor can see how the business builds up into something which, with lots of customers, will clearly cover it's variable and selling costs, and then corporate overhead, and ultimately drive profits.
• Competition – be honest and expansive. In addition to the obvious direct competitors, give some thought to the other questions investors will ask. "Why couldn't Google build this and crush you?" "Is this really a big enough pain point that the status quo won't prevail?" "Can't big customers just build this themselves?"
• Go to Market Strategy – we alluded to it in the Unit Economics, but this has got to be a believable story about how you acquire customers and, hopefully, do it at ever decreasing costs/customer.
The above may be painfully obvious to some, but there's nuance within each for any particular situation. Again, I encourage you to get an "expert" on these processes to walk through each of these sections and think comprehensively about how they apply to your business.
Some of this work will result in you tweaking the arc of your story a bit. But much of it will not. This work will become your "back pocket" analysis – things you'll do the work on and then keep handy, knowing you're likely to be asked. I can tell you that there are few things that impress a VC more than asking what they think is a brilliant, insightful question and then having the team come back immediately with an answer of "Great question. We've thought a lot about that. Let me share some analysis." If it's well-packaged and pretty analysis, so much the better. It's the kind of thing that leads the VC to go back to her partners and say, "Man, these guys are good. We asked a couple of deep dive questions on tough issues andthey were way out ahead of us – they'd already done the work. They've really thought through and deeply understand their business."