Most people prepare for these meetings by rehearsing what they're going to say. The better preparation is figuring out what they're going to be asked.
An executive walking into a meeting with you is almost always trying to answer one of a small number of questions: is this on track, does this need my help, or does this need my decision. If you walk in with a strong narrative about your work but no clear read on which of those three questions they actually have, you'll spend the meeting talking past what they came for.
Before the meeting, write down, literally, on paper or in a note, the single headline you'd give if you only had one sentence. If you can't compress your update into one sentence, you haven't finished preparing yet, no matter how much you know about the details.
Headline: "The migration is on track for the 15th, and I need a decision on whether we freeze new feature requests during the final two weeks."
That single sentence tells the executive exactly what kind of meeting this is going to be, a status check with one decision attached, before you've said anything else. Everything you prepared beyond that sentence exists to support it if they ask, not to replace it.
From there, prepare for two things specifically: the number they're most likely to ask for, and the objection they're most likely to raise. If your update touches budget, timeline, or headcount, know that number cold, not "I'll have to check," but the actual figure. And think honestly about the one thing in your plan a skeptical executive would poke at, then have your answer ready before they ask, not while they're asking.
Bring less material than you think you need, not more. A first-time manager's instinct is to over-prepare, twelve slides, every possible data cut, every contingency, as insurance against being caught off guard. Executives rarely want the insurance. They want the headline, the number, and the decision they're there to make. Anything beyond that belongs in an appendix you only open if asked, not the first thing you present.
Last piece: know before you walk in whether you're actually asking for a decision or just informing them. If you need a decision, say that explicitly at the start, "I need a call on X by the end of this meeting", instead of hoping it emerges naturally from the conversation. Executives are used to making decisions quickly once the question is put to them directly. What slows them down is a vague update they have to reverse-engineer into a question themselves.