Using your voice is so important for classroom management of all grades. I find it to be something especially useful for intermediate grades, however.
Something I have personally struggled with is to make myself sound more assertive in a classroom. Really working to make your voice into a more powerful, “teacher-like” tone is extremely useful in getting a class to pay attention to what you are saying. Working your voice and differentiating your tone does wonders with the different types of things you are trying to convey to your class. Whatever tone you use, make sure that you have that commanding presence come through in your voice. It may seem as a small or obvious thing, but it really helps yourself, and your class, to flourish!