I've designed pitch decks for Series A, B, C, and D rounds.
The mistake I see at every stage is the same one.
The deck makes the investor work TOO hard.
Too many slides. Too much text. No clear flow. Investors spend about 2-3 minutes reviewing a deck before deciding to take a meeting. If they have to think carefully just to understand what the company does, most won't reach slide five.
The presentations that got meetings all had the same thing going for them: each slide earned the next one. The investor was always a step ahead, wanting more.
One thing I tell every founder before we start: read your deck out loud, from the first slide to the last. If you catch yourself explaining a slide out loud, that slide isn't working. The slide should do that job on its own.
The cover slide alone kills more meetings than most founders realize. If it doesn't answer "what does this company do, who is it for, and why now," a lot of investors stop right there.
What do you think it's the hardest part of a deck to get right?