Forgetting when delivering a bayaan

I listen to Islamic lectures, 6 points and talks all the time and I always forget what they say almost instantly but afterwards if someone talks about a section from it I am able to easily recall it most of the time. But sometimes when I am in Jamat/Tableegh/Path of Allah, and I become appointed to give a bayaan/ talk on 6 points or something I can barely recall or access anything in my memory even though I have so much knowledge about it somewhere in my memory. What should I do?