Do your children have a spelling glossary? I have had people ask me this question.
To answer we not only have a hand written notebook that each child will fill out as they come across things that they need to remember or a concept they keep getting wrong. This is a great place to have them copy down the correct rule. But we also have it online version of a spelling glossary.
Another reason we love time4learning.com, there are tons of resources that we use daily. Copying the definition from the online glossary is a great way to help your children remember what they have learned.