High end clients, how do I show I am capable without any experience?

[Luke Richard]

I have recently started a property management company with a colleague and we have had a stroke of luck where a client was asking us to try and find him a commercial property that is of significant worth. We are fully capable of taking on a project like this but my concern is that I will do something that will communicate that I am new to the business and he will lose interest. What are some important things I need to know in order to avoid looking inexperienced, or what can I do to impress someone like this? I understand that this is probably a long shot but it will definitely be good practice for us even if it doesn't work out.