I'm going to let you in on a two little secrets that I use to teach pronouns as a sort of Christmas present....
1) For she/he: I usually tell my students that "hers" and "his" are dead...not an option....not a choice. It is a little bit harsh, but I have found that my students will always use these two words if I don't place heavy emphasis on not using those words.
2) I use the Pronoun Parade deck from Super Duper to drill my older students. We've turned it into a competition of sorts....whoever says the correct pronoun the fastest and in a complete sentence earns the card. They obviously want to earn the most cards so it's a great motivating tool. It usually takes about three minutes for us to go through all of the cards.
I love this card deck as it's a versatile tool. I use it for describing images, who questions, and formulating sentences.
Now, I have another idea for teaching pronouns that I will share with you in my next post.