You need to know you have something that will be of value to them. So, do your homework, read the annual report and look for things in their strategy that you solve. Listen to earnings calls, and correlate you business to needs you hear on those. Pull a strategy together that is a direct use case from their position on how they make money with your help. Then reach out to the CEO, CMO, Strategy leads on LinkedIn and make the connection with the items you KNOW are of interest to them. Expect this to take 9-18 months, and a lot of meetings, cost, and time. You should also have exactly what you want "The Ask" in the deal, and present that earlier than later, because a "NO" answer can be more valuable than a "Maybe".