You have to pretwist, reverse direction, the lays between the first and second loop. Make the first loop, you'll see that this process leaves twist opposite the direction used to create the loop (if you don't let the tag end of the lays "unwind" by themselves). Take all that out, then reverse it say 15 to 20 turns. When you twist the second loop, you'll be twisting in the other direction, taking these twists back out. That's why the call it reverse twist, and the secret to the strenght of any (twisted) cordage. When you finish, ideally, the center of the string will be straight or nearly straight and the loops tightly reverse twisted (where the twist in lays individually offsets the twist in the lays combined).