Read to the class. As you read aloud, let your students know when there are commas in sentences. For example, when you read a sentence with commas, pause for an extra second when you reach the commas: "Scruffy, Mary's dog, ran around the yard today."
Allow students to point out commas when they read. Give each student a book to follow along in as you read to them during circle time. Ask the students to raise their hands every time there is a comma in the story.
Ask the students to practice using commas by assigning them different writing activities during class. Instead of grading every writing activity, let the students experiment. Walk around to their desks to check their progress. Praise the students who use proper commas in their sentences and offer your help to those who struggle.
Write sentences on the board without commas. For example, write, "Tom Janet's brother has big blue eyes and short brown hair." Ask students to come to the board and put commas in the appropriate places. Reward the students who use commas correctly with a sticker or a piece of candy.