Pretty simple for me, at both my start-ups: Keep Showing Up. In Person.
Both the super critical, super large deals I closed that made each company took way longer from first meeting to close than I even expected. Over a year in each case, from the initial pilot / handshake to close.
They key was simple: going there in person. Not (just) phone calls and emails. As often as they’d meet with me. At least every 45 days. Checking in. Giving updates. Sharing product news. Just having a coffee.
Did that accelerate the deal? Not sure. But it always kept us top of mind, and in the game. It kept the deal at least moving on.