as Vlad said, a bit of context might be helpful.
In my business, I have relatively frequent interaction with top management and CXO level of large companies and enterprises, so I may be able to give you a few pointers.
First of all, and most importantly: These people are humans, too. They have good and bad days, they look forward to their holidays and they sometimes worry about their kids. So don't expect a robot, and don't be one.
Secondly: Most of these people are both very smart and very experienced. They know most tricks in the book, so bullshitting them is very risky business. So know your stuff! Also, if you don't know something, it's better to make that clear rather than making something up. depending on how confident you are you can either go the: "I definitely don't know this for certain, but my hypothesis / educated guess / gut feeling would be..." of the "I am absolutely not sure about this, please give me a few minutes / a day / a week after our meeting and I'll get you the correct answer rather than telling you something inaccurate." Obviously, you really should know your stuff, so this should not happen in territory you're supposed to be familiar with!
Thirdly: Context matters. If you're in a formal meeting with a set agenda, you'll be more to the point, than when you're winding down at a hotel ar at 11 pm. You mentioned that this was a "discovery meeting", so I assume it's a semi-formal setting: This is an official, scheduled meeting, but no set agenda. The best way to get the most out of these meetings is to get the other person to talk - ideally, you talk 20% of the time, the other person 80%
Fourth: Personality matters. Just because they have a C in front of their title, does not mean they are all the same. You'll have introverts and extroverts, analysts and creatives. Try to be empathetic and get a feel for what makes the other person tick. Guennael's story is certainly a good example of how he hit the right nerve with that CFO - it might have totally backfired with a different executive. Try to see whether you can find interviews, ideally longer, "off the cuff", interviews of the person you're meeting. Or talks they've given, ideally something like TED talks. You may spot patterns, like them diving into details or not answering certain questions straight, or using a lot of "storytelling", maybe from personal experience. That can give you an initial feel for the person.
Five: These are extremely busy people, so be mindful of their time. Make it clear that you value their time and don't take it for granted.
Six: As always, try to be relaxed, friendly and open.
Hope this helps,