I’ve read several articles such as this one (I can’t find the original article that I read about this, but there’s plenty out there) that talk about how the key to memorization is the act of recalling. So repetitively reading a script or passage will only go so far (this is the phase where your brain is loading it into your short term memory) but it’s the crucial recalling of that information that forms and strengthens the neural pathways, so the quicker you put down that script and start trying to remember it, the quicker you will strengthen those neural pathways and have the text memorized. Don’t spend hours re-reading something a thousand times. Only once you put it down and begin actually trying to remember it will you start the important phase of the process.