Collars act like a frame to the most important picture in the world, your face. To choose a well designed frame, it must complement the picture. For a collar, choose one that is opposite to the shape of your face shape, as explained in more detail below.
There are two main steps in choosing your collar
Stand in front of a full length mirrorImagine a string is attached to your head, pulling your body straight as the picture shows below
Imagine a line pulling your head to get the ideal posture
Study the size and dimensions of your head and face carefully, and put them in one of the following catagories.
Infinitely many different kinds of faces exist, but for the purpose of choosing a shirt collar, let us classify them into two catagories, they are,
Line diagram of a narrow and long face
Rectangular, heart and diamond shaped faces can also be classified under the long and narrow face. They key thing to look out for is the jaw line and cheeks. A thin or sunken cheek or small jawline will indicate your are the long and narrow facial shape.
For such faces, use a spread collar.The horizontal lines of a spread collar will counterbalance the long vertical lines in your face created by the cheekbones and jaw line.
This shape is what it says, a face without sharp angles and tending to be wider at the cheeks and having softer "corners" along the jaw-line and forehead.
Line diagram of a round and wide face.
Double chined faces are usually catagorised under the round and wide face.
The job of a collar is the lengthen the round and wide face, making it apprear long and slender. Use narrow, point collars on round faces, or tabbed collars. These will help to achieve the desired illusion.
If you belong to the tall and lanky group, chances are you have a longer than usual neck. Instead of resigning yourself to look like a stork, you can hide this by increasing your collar height. However, this can only be done at a tailor. No clothing manufacturer vary their collar height currently.
Tom Wolfe's freakishly high collar does a lovely job of hiding his long neck
Line diagram of an unproportionately long neck in a low collar. The large amount of neck line exposed is undesirable.
Line diagram of a two button high collar for long necks. This will make your neck seem more proportional to the rest of your body.
Three button horror of a collar for giraffes among us.
Use a larger, longer collar, at least 3 inches in length. A small collar below a large head will only make you look ridiculous.
For those with large heads, stay away from small collars! Work with your tailor to find the optimum size for you.