I just repeat it over and over to myself and I've got it down. But if you're not a good memorizer, you can always try going onto youtube and listening to a frequency that helps boost memory. If it's really hard for me to memorize something and I seriously can't get it, I generally resort to turning what I'm trying to memorize into an imaginary person that follows me around and annoys me. Eventually I get so annoyed and frustrated at them that the next time I try to memorize it, I can get it down super fast. But that's just me.