When I was starting in my teaching profession, I was also you that is having a hard time with communication skills because I am afraid to make mistake but as the time goes by and I learn how to speak in front of the class I manage to speak and communicate easily. The reason for that is that you just need to trust yourself and just encourage yourself that you can do it. Face what you are being afraid of and overcome it and you will see as the time goes by then you cannot notice that you are getting better and better and a good speaker on that day.