Sales isn't sales.
Sales is helping prospects see value, see what's possible, see the future state of where they can be, and a way to get there.
Communicated by engaging, showing, informing.
Some practical tips.
Start with list of points to cover on one slide (2 if absolutely necessary) including demo highlights previously captured in discovery. And tweaked from your experience knowing the priorities of the audience. A simple list, not a slick "presentation" slide with logo and all. Not salesy.
If people interject, or suggest another point, then engage and see if others agree.
Look around the room for non-visual reactions. Gently ask if someone looks skeptical. Avoid going around the room asking, this slows things down while people are evaluating you, your offering, your company, and possibly thinking about other things. You can lose credibility quickly. Hesitation, long pauses, too many questions are interpreted as low competence --> lower confidence in you.
Use short and long pauses. This is an art, and elicits powerful responses.
Show a simplified block diagram only if absolutely necessary, such as showing distribution of the prospect's data to their clients if that's a "thing" for this audience. If they can grokk your value without a diagram, skip it. Less is more.
First demo as a "day in the life" from different perspectives (dashboards for execs, status for ops, metrics for marketing).
Target for a 3 minute demo. Rehearse with your team until you can do this faultlessly.
So if senior people have to leave, they have seen the VALUE of your offering. They will engage further, ask you to show others, etc.
Earns confidence through competence.
If your demo is good, you WILL get questions, reactions, skepticism, challenges. That's GREAT!
Get confirmation, ask for feedback, ensure you are meeting expectations. Display a list of points raised on a laptop as a live document in front of everyone. At this point, you're responding to the prospect, engaging visually, partnering...and doing this with the GROUP -- completely different from engaging 1:1 with stakeholders. Who is an influencer? Who is a skeptic? Who likes this? Who doesn't? Who has fears? Who may be a champion?
The AE has setup the meeting knowing who will attend, their concerns and roles. So you'll be ready to do deep-dives, or breadth-first responses across multiple perspectives, on-the-fly.
From this point, you can gauge what to prioritize, what to do next. A more detailed architecture. A longer demo showing more value, a version showing "how" dashboards are created, performance metrics, etc.