High level execs tend to have their attention torn in a million directions at once. This means that how you communicate with them can be very important.
1. Always provide context for what it is you’re bringing up and be specific. “Can we get your sign-off on the Foo project?” isn’t very helpful. This puts the burden is on them to context-switch, which they’ll almost certainly have to do in order to grok what you’re talking about. Better would be: “You probably remember how last month we discussed setting up Foo to protect against intrusions like the one detected in June against the Bar cluster. We’re almost done with the project and in order to meet the deadline we just need you to review and approve the BazQuux by Friday.”
2. Summarize. You probably could provide a 3-page writeup of the decision making process that went into choosing a vendor, for instance. Your exec probably doesn’t have time to read it. Instead, provide a few short bullets: “We evaluated vendors Foo, Bar, and Baz for the Quux project. Our recommendation is to use Baz for the following reasons: <insert 3 short bulleted sentences>. If an alternative is needed, Foo would also satisfy our critical requirements.” And then just be ready to provide more detail upon request.