Because it's so thin, a crepe cooks very quickly. Check to see if it's done after about one minute. Simply lift one edge of the crepe with a spatula, and gently shake the pan. If the edges of the crepe appear to be crisp, the underside is brown, and it shakes loose from the pan, it's time to turn. It will need to cook only briefly―about 30 seconds―on the other side, just long enough to set the center of the crepe.
Crepes are a choice make-ahead food. You can cook them up to four or five days in advance, stack them between layers of wax paper, slip them in a large zip-top plastic bag, seal, and refrigerate. They will also keep in the freezer for up to two months. If freezing, make sure to stack the crepes between layers of wax paper and wrap them securely with a double layer of plastic wrap. Be sure to allow the frozen crepes to thaw overnight in the refrigerator before using.