Using the microscope is a skill that most 6th graders need to practice. Even if they have used a microscope in elementary school, I find that many are still uncomfortable with using one. Often they are afraid they are are going to break the 'scope or a slide. And they are almost never sure of what they are seeing.
They only way around this is practice, lots of practice. I have several investigations I use to help students get this practice.
You can find them HERE.