Introduce letter writing by reading aloud several picture books on the topic. "Messages in the Mailbox: How to Write a Letter" by Loreen Leedy is an excellent nonfiction picture book about friendly letters.
Show a letter template to the class and make a copy for each student. Keep the template on display in the classroom. Label and number the four parts of the letter template for reference. For example, write a number one next to the date and two next to the salutation.
Model writing a letter to parents and give students time to compose a letter to their parents in a composition book. Remind the students to read their letter when they finish writing.
Model how the students can check their letters against the template.The students will then revise and edit the letters.
Check over the letters as the students finish. Use the template numbers to help students correct errors. For example, if a student has omitted the closing you can tell the student to check for number four in their letter.
Instruct the students to take their letters home for the parents to read. After the parents read the letter, they write a reply on the next page in the composition book.