I respectfully, but completely disagree with this advice. There is nothing to be gained by making yourself look like anything that are you are not, and there is a fatal flaw to this mentality:
The 'big fish' clients are (by definition) more successful and experienced than the vendor who is still trying to land their first 'big fish' client. In almost every case, the 'big fish' client will see right through any effort that a little company or freelancer makes to look like a 'big successful company'. In fact, that is the hallmark of the inexperienced vendor - an obvious freelancer or one-man-show who keeps saying 'we', calls them self a CEO and throwing out corporate-speak. The funny thing is how transparent it is - a quick check on the internet can tell me if a company is a big company or just a single person, but usually I can tell from the get go.
If you are trying to move towards bigger clients, don't fake anything. Just be professional, do great work, be available, be on time, charge competitive rates, and above anything else make those big fish clients feel like they can trust you. It's that trust that brings you to the big leagues.