1. You should mime the picture and make your classmates guess what it is.
2. You have to use gestures to make your friends guess what the picture is about.
3. Mime the picture and make them understand what you want to do.
4. You can use body language, but don't say at all. By gestures, you have to make them guess what the picture is about.
5. Look at the boy. What is he trying to do? Is he trying to drive a vehicle?
Guess what he is trying to do.
6. Come up here and look at the picture I am holding. And make the students say what you are trying to do.
7. You can use body language. You can move your body parts. You can use gestures. However, don't talk at all.
(Are the expressions all grammatical? Check them, please. I appreciate your help.)
In 4, you should change "say" to "speak."
In 6, it'd be better to use "tell" rather than "say."
The rest reads fine!
=)