Note the Greek letters. By and large fraternities are identified by a series of two or three of the twenty-four Greek letters. Like the English alphabet, the order of the letters is important, and effect the meaning accordingly.
Note the colors in use. Fraternities traditionally adopt colors which serve as identifiers, and often embody meanings known only by the members.
Pay attention to the shape. Occasionally, fraternity pins may embody a certain shape, which in itself bears special meaning. Phi Beta Kappa often uses a key, the meaning of which is reflected in the fraternity's belief that the love of wisdom is the guide to life.
Look for adopted mascots. Many fraternities have adopted mascots, either officially or unofficially. These mascots turn up on fraternity pins, cuff links and other items.