For a simple answer, I would say, choose a wedding photographer by looking at other weddings they have shot. If that work would satisfy your requirements, then you are done…assuming you can afford it. There are other details, for sure, and this issue can become quite complex and difficult, but if you have found a wedding photographer who has already consistently produced the quality and style of work you want, then you will most likely be very happy with the results.
I have one caveat to that. When checking out wedding photography, make sure you look through a full album from one wedding. A photographer’s “greatest hits” only tell you that they will have a couple keepers from each wedding. See how a photographer covered one full day. For something as important as a wedding, most of us want a professional who can consistently capture photos throughout the day.