Decide on the shape of crest. In most cases, crests are designed with the simple shield shape, but some crests are designed with three tines at the top or with a flourish at the apex. You can also decide whether your crest will be narrow or wide. There is a great deal of historical variation, so it is simply a matter of preference.
Decide on the colors. The colors of your crest will usually be those of your school, but remember that a crest should be visible and easy to distinguish from a distance. Most historical crests have a light background and dark detailing. If your school colors are maroon and gray, this might make for some readability problems. Remember that dark figures on a pale background are always more recognizable than the reverse.
Consider dividing the crest. Many medieval crests were divided in half down the middle or into thirds. Most of the time this division happened in vertical divisions, but in some cases, it could happen horizontally as well. Use chevrons, wavy lines or straight bars to divide your crest, and these divisions can add a very dramatic feel to the image.
Select the animals or figures that might go on the shield. If your school has an animal mascot, it can often be placed on the shield quite handily. Animals, whether they are real or mythological, will be the supporters, the things that traditionally secure the shield as well as give it meaning. Lions, hawks and wolves are often used as supporters, but so are mythological animals like unicorns and griffons.
Select a motto. A motto can often be inscribed on a scrolling ribbon underneath your crest. While most historical mottoes were in Latin, remember that that was during a time when more people read Latin. Consider inscribing your school motto in English unless you have someone who is skilled with Latin and can give you a good translation.