In almost all jobs, there is a need to receive and give directions. Help others be right. People want to be right and sense support and agreement. Be less critical and more supportive.
People feel better and are more likely to cooperate with someone who is confident.
Retain you poise. Stressful circumstances and persons opposed to your ideas can cause a loss of composure, which hurts your image in the eyes of others. Explain what is needed, what should be done, etc. Long conversations, or overly complicated directions cause people to become confused and frustrated. Have confidence in what you say.