This is good questionnaire to use as a spring board for discussing correctness in writing. I've had excellent discussions using these questions. This is also adapted from Peter Miller's now out of print
Becoming a Writer. Think about your speaking and writing to find answers to the following questions.
1. Do you make mistakes in speaking? What are they?
2. Do the mistakes you make in speaking interfere with your ability to express yourself to any great extent? Explain.
3. How do you detect and correct your own mistakes in speaking?
4. Do the same kinds of mistakes occur in both speaking and writing? Can you detect and correct them in the same manner? Explain.
5. Are there any kinds of mistakes than can happen in writing that do not occur in speaking? Explain.
6. Do mistakes in writing interfere with your expression when you are writing only for yourself? Explain.