How are Shabbat candles lit?

The Ashkenazi custom: light the candles first, then cover the eyes with the hands, recite the blessing, and only then look at the flames. This order exists because saying the blessing normally 'accepts' Shabbat, after which lighting fire would be forbidden. By covering the eyes during the blessing and 'revealing' the light afterward, the woman experiences the light as new, maintaining the principle that blessings should precede the act.