If you are called by God to preach, then, remind yourself that He is with you. He is greater than the fear. We do get afraid, but He is not the One who makes us afraid. If we put our focus on Him and the truth that His Grace Is Sufficient For Us, then, we can do what He has called us to do and we can do it successfully, as we trust Him. When you go to preach this evening, do so as unto the Lord. He is the One who gives the Truth to preach. He is the Truth and He is able to give you the words. Don't allow yourself to give into the fear, instead, pray and ask Him to use you to perform His Perfect Will in this time. And preach what He gives you "to Him". Yes, you will have listeners, but give this service to Him and let Him annoint you to do the work He has given you. I believe as you trust Him and you do it "as unto the Lord", you will see that He has used you and it will be alright. He never leaves you nor forsakes you. And, don't be afraid as He will keep you as you trust Him.
To overcome stage fright, it will take you to go in front of people a few times which might take 4 or 5 times to really get over stage fright. You will have to understand what your audience is seeing by recording yourself giving the presentation, watching it, adjusting your delivery or content, and then recording it again. The fastest and most effective method to get rid stage fear is hypnosis. Hypnotic sessions with a hypnotherapist can cost up to around $70 per hour. For more information, visit http://www.forbes.com/sites/tjwalker/2011/03/01/how-can-i-get-over-stage-fright-or-nervousness/.
All people deal with it differently. It helps some people by crying before they go on stage to get rid of some of the stress. And sometimes people drink a little bit before they go on stage. (this is not recommended by me, but if you want to only do it if you are old enough to drink.) You might be able to develop your own way of dealing with it.