"Mistakes and pressure are inevitable; the secret to getting past them is to stay calm... New research shows that most of us go about staying calm the wrong way." - Travis Bradberry
Calm, and even confidence, comes from our heading in the direction of the cause of nerves and turning our "anxiety into energy and excitement." From a 'firm foundation' (God's strength in our weakness, not losing sight of the peace we have in Christ, and being slow to speak), we can exercise Bradberry's approach to calm: "Staying composed, focused, and effective under pressure are all about your mentality. People who successfully manage crises are able to channel their emotions into producing the behavior that they want."
Questions to ask are:
How do I really want to respond to this situation?
What's the worse that will result?
Will this matter in 5 years?
Am I overly focused on me, and not the problem?