Intonation matters.

Did you know that 38% of meaning is communicated through tone and voice. Why do you need to know that? Well, if only to use it properly. Learn to manage your tone. No quiet statements under your breath. Everything should be clear and loud, (but not too much so that you can be heard in the next room). Your speech should be slow with short pauses. And remember, no commanding tone, you won't gain credibility that way, I'm telling you that for sure.