I started the practice cards just after Thanksgiving. I bought a small pocket chart (you can see a picture of it on my blog) to hold the cards which I ran on cardstock and each child has a pocket. I start each day doing the frownie point for the class for misbehavior hoping the repeating of the rule will bring them around. If it becomes evident that one or more particular kids are continual problems, that's when I assign practice cards (no more than 2 per day). They get the card in their pocket, have to practice 2 minutes at recess, and fill out their parent letter and have it signed. Once the letter is signed, the card is removed from the pocket. I have actually instituted a step before assigning a card. I pick up the pile of practice cards for the rule that's being broken and announce "I have practice cards in my pocket." Most of the time, this makes the offenders shape up and I don't have to use the cards. They learned early on, practice cards are not fun!
I have also tweaked the practice card letter that goes home. (If you'd like a copy, give me your email and I'll send it. I can't seem to attach it here.) I wanted the kids to verbalize the misbehavior so they knew exactly why they got the card. I was amazed how often the kids didn't know what they were receiving the practice card for! So I added a box where they can write the "offense". This way the parents also know exactly what happened.
Lastly, I keep all the signed practice card letters. They make great documentation should you ever need it.
Good Luck!
Kate
http://katebowski.blogspot.com/ 
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