I always had a serious fear of public speaking. I forced myself to do it when I had to & avoided it when I could. At first I thought perhaps by doing it I'd eventually overcome it. But I never did. So I'm afraid I don't have any great advice to offer you. However here are links to 4 articles, from PsychCentral's archives, that talk about overcoming the fear of public speaking:

Panicked Over Public Speaking? A Holistic Approach That Helps

Fear of Public Speaking | Healthy Romantic Relationships

How to Overcome Stage Fright in Almost Any Situation

6 Tips for Overcoming Performance and Test Anxiety