You only had to seek out the saddest, most down-trodden, marginalized woman in the community, and voila! you'd find your witch. All the better if she were sickly in body or mind, and had no one to protect her.
And you could have turned her over to the authorities, and see if she could prove her innocence. (Will she sink or float when tossed in water? Remember, the godly will sink! Does she have Devil's marks--extra nipples--or odd shaped birthmarks? Could she recite the Lord's Prayer without stumbling?)
So if you--or any of your friends--had become cursed, here is what you would have needed to do:
Get a bottle of urine from the accursed. Bury the bottle in a dung-hill. Keep careful watch. The witch will be drawn to the dung-hill and will demand the bottle.
No matter how she pleads and curses, you can not give her the bottle. Eventually she will die, thus breaking the curse.
So simple to get rid of a witch, right? Sure.
But of course, the trials weren't about stopping her powers, at least not the supernatural kind. They were about asserting moral and patriarchal authority, and no amount of urine buried in dung would bring about the same ends.
Just something to consider this Halloween!