Mastering purpose and tone in IELTS General Training Writing Task 1 is essential for achieving Band 7 or higher. By addressing all the bullet points thoroughly and ensuring your language matches the formality required by the recipient, you will meet the criteria for Task Achievement, Coherence & Cohesion, and Lexical Resource. Regular practice, along with a clear understanding of when to use formal, informal, or semi-formal tone, will allow you to write letters that are both well-developed and appropriately styled.