One thing I would recommend is deciding on the fish you want before buying the tank, or you may be, like me....restricted in what you can get. For example, I would have 'tang city' if I could, but even one tang in a 55 is not a good idea, so I limited myself do to my own personal ignorance. Also, the bigger the tanks, the more fish you can have, depending on sizes of course. If I had it to do over again...I would have started with a much larger tank, but still....start slow.
Good luck and welcome!