Sale to a large Asian bank: Met an influential person at the bank who thought I am smart and sincere. He pitched to 5 departments at the bank on my behalf that got me meetings. I reinforced mine and my team's credibility at the meetings and committed to delivering. (revenue over $200k from this client)
Sale to a large US Bank (we're based in Singapore): Contacted via cold email stating our exact value and past client work. Ended up being the right guy who sold us to 5 departments internally. One worked out immediately. Took 6 months to complete legal procedures but the sale happened without ever meeting face to face. We said the right things which showed we understood their problems exactly, had solutions and credibility.
Conclusion: You need to present yourself in the most credible way possible, show that you and your team are resourceful and are committed to delivering no matter what. Then most importantly, you need to find a "hero" within the organization who sells you internally. Stick with this hero.