I've heard some successful people mentioning "fake it till you make it", but the same people also say things like "over sell yourself, show you are confident, but make sure that you actually live up to your word"
A good example of faking till you make it that won't end up destroying your reputation, is to imply towards people that your company is a little bit bigger and more experienced than it is, while in reality you only recently started out and have only a couple of customers.
Because as long as you perform top quality work for clients and live up to your word, you will never get busted for exaggerating a bit in your sales speech.
Those initial 5-10 positive feedbacks from clients can be crucial before your business can start growing faster. People in general are biased as fuck, if something is popular, it will automatically sell more (initially at least) than if it has no reviews at all.
At least this is what my experience on outsourcing bureaus tells me, the difference between 3-4 positive feedback comments on your profile and none, is night and day as far as attracting customers go.