How to cut a lemon for squeezing?

So, I'm in the kitchen trying to make some fresh lemonade, but I'm stuck on the first step: how do I properly cut a lemon for squeezing? Do I just slice it in half and squeeze away, or is there a more efficient way to get all the juicy goodness out? I've heard about cutting off the ends and rolling it on the counter, but I'm not sure if that's necessary or just a trick. Help me out here, what's the best way to cut a lemon for squeezing?