Don't memorize a script.
It might be common wisdom to memorize your script for a presentation, but like a lot of common wisdom it is wrong.
A script - written or recited from memory - separates the source from the recipient. When I recite a script from memory, my listeners might be affected by me but I cannot be affected by them. I cannot be with them in the present because I'm reciting words from the past. I cannot respond to who they are in the moment. I cannot form a relationship with them. Isn't that what separates authentic speaking from writing?