In a prison setting with a stable group I made name plates to set on floor in front of each man for the first two weeks. After that I knew them. In the jail setting we have new people every week. I use stick on nametags (which need to be removed after class—check with your institution on its policy about this). I pass around baggies with the nametags, a marker, and stickers for decorating. Sometimes the stickers connect with the story which provides a hook for remembering it.
How and whether or not you take attendance depends on your setting and goals. At the jail I track attendance to know who has earned which perk (a folder for attending twice, a certificate for attending 4 times, a book for attending 6 times). The chaplain also has a form for attendance which is passed around for participants to sign.