To get started, you will need a file folder for each student. Cut 2 slits in the front cover, so that the folder has 3 flaps that can be raised. Then, staple a Weekly Spelling Sheet inside. Label the first flap "List". Label the second flap "Pre-Test". Label the third flap "Post Test".
To create the Weekly Spelling Sheet, choose 5 words that were spelled incorrectly on last week's test by the most students.
I found this was a great way to individualize spelling so that all of my students were challenged. Best of all, I was able to still give just one test on Fridays. I hope someone finds this useful.