well, what i do, is just read it over and over again and eventually it just sinks in. or if you really know what you're talking about, you can just bs your way through lol.
Like what kchi said, read it over and over again. Dont put the paper down and try to remember whats on the paper, that causes stress in the brain and that makes you lose your memory.
write down all the main ideas in short point form. Memorize that and just fill in the gaps yourself with your most eloquent vocal abilities when it comes times to repeat it.
edit - n/m, i guess today is "tomorrow". too late lol...but remember what i said for next time.