Ground every claim in real numbers and real systems; never fabricate.
Always ground claims in real numbers — photos, books, a decade of trips made queryable — and real systems. Never fabricate metrics or testimonials.
Anyone can assert. A slide claiming a result costs nothing to make and nothing to believe, which is precisely why it convinces nobody who's seen a few. The market for confident claims is saturated; the market for verifiable ones is not.
So the rule is simple and load-bearing: the number has to be real, and the system has to actually run. A specific, checkable figure is worth more than an impressive round one — partly because it's true, and partly because specificity is itself evidence you did the thing.
The discipline costs something, and that's the point. You occasionally can't make the claim you'd like to, because the data doesn't support it. Saying the smaller true thing is what makes the bigger true things believable.