I am one of the worst people for learning lines. I practice, I read them over and over and over and over again, but I just can never remember all of my lines. I love lists, by the way, so you better get used to me making lists.
1. Say It Out Loud
You are going to be performing it out loud, so why shouldn't you practice it out loud. I mean, sometimes you can practice by just reading, but saying it out loud is more practical.
2. Other People
When you have lines, you have to remember that there are lines before it, so you need to know your cues. What good is it if you memorize your lines and then you don't know when to say them?
If you already know your blocking, practice your lines with the blocking. It actually helps a lot, because if you, let's say, stand up at one point, you have a better chance of remembering the line with the action, instead of having the two split up.
If you have nothing to do during class or something, write your lines from memory(if you can) or with some help from the script. If you write it out a lot, or even type it, it will stick in your memory. It helps me, a bit, at least.