Keep in mind three things and use these to guide your selection and decision making process:

Personality - Service - Product

Chat to them first and ask general questions. Do they make you feel at ease? If so, they are more likely to be able to put you at ease on your wedding day and capture natural, relaxed photographs of you.

How will they fit into your wedding day? Would this photographer fit in as one of your guests? Are they going to whisk you away for an hour or more? Or will they be trying to remain anonymous and invisible?

Does their style fit with your wedding day and your ideas of wedding photographs?

Now take a closer look at their work. Look at the quality of printing and paper. Feel the albums they show you and look at the design and layout.

Does their work ooze quality throughout?

If they pass the 'Personality - Service - Product' test, book that photographer before someone else does.