There a few factors brides should consider when choosing a veil, such as you face shape, body shape, hairstyle, and wedding location.
A veil will frame your face, so taking into consideration your face shape is important. For a square face, it is preferable to have a veil that is at least shoulder length, since usually a square face is wider than it is long and it may be desirable to add length to the face. You also might consider having some volume on the top of the head. Circular and cascading veil styles can also help soften the lines of a square face.
A bride with a round face would generally want to avoid veils with a lot of volume at the sides of the head, since this will make her face look wide. Choose veils that are long and cascading, as this will make the face appear slimmer.
An oval face is slightly longer than it is wide, and is usually well-balanced, so this bride can be free to experiment with various veil styles. However, it would be wise to avoid extremes in volume or width, so as to maintain your proportions.
Those with a rectangular face would look best in veils that have width around the face, and should avoid height on top of their head so as not to add to the length of their face.
Brides with large busts can benefit from a veil that is fingertip length or longer, because length in the veil can help elongate the upper body.
Pear-shaped women tend to look best in veils that end at the shoulder, elbow, or waist level. These lengths draw attention to your small waist, rather then the width of your hips.
Tall women can typically carry off longer veils, especially cathedral length, but shorter women tend to suit veils that are waist height or above.
Please keep in mind that these are just general guidelines based on advice from professionals. But ultimately- you should wear what YOU want. It is your wedding day, and a wedding planner will be the first one to tell you that you should do what you want because it's all about you!! :)
Also, please check out my veil styleboard featured over on Bride Chic, and the gorgeous veils made be Amy-Jo Tatum! Stay tuned for The Bridal Veil 103 where we'll discuss how your chosen hairstyle and wedding location can effect your veil choice.