Consider how subtle physical cues, including your body language, breath rate, pace of speech, tone of voice, and facial expressions, create reciprocal responses in your students and classroom culture.
Attempting to create order by yelling or using controlling and aggressive tones in the classroom, for instance, will actually have the opposite effect. Students will respond to these physical cues by becoming further escalated or fearful, creating a negative feedback loop that results in a decidedly unsafe classroom culture.
Instead, try shifting your physical presentation to be more congruent with the type of response and culture you would like to create. The more calmness you can bring through a slower pace of speech, deeper and slower breaths, and calm gentle tones the more your students will feel safe and at ease.
Of course, this requires that you first have an awareness of what you are modeling externally from moment to moment. This type of awareness is generally only cultivated through an ongoing mindfulness practice.
One way to quickly bring awareness to your external modeling is to set a handful of random alarms on your phone throughout the day. Each time you feel it buzz, take a brief moment to check in with your physical sensations. How quickly are you speaking? Is your breath shallow of full? Is your posture open and receptive, or closed and guarded? Are you smiling or frowning? Notice how these small adjustments effect your students.