When considering a Hair style for your wedding day, get acquainted with your face shape (heart, square, round, oval, diamond, etc.). There are some very clear tricks to add symmetry to the face, a lot of it can be done with makeup tricks including contouring but the hair style plays a big part in this as well.
Make sure you chose something that you'll be comfortable with and that most of all fits in with the overall feel of your style of dress. Identify whether you want to be classic, romantic, unique, glamorous, etc. as this will help with the final hair look (view my other blog regarding "choosing a look")
Most importantly, have realistic expectations... what looks good on your favourite celebrity on the red carpet may not suit you or look the same on you.