Some necklaces I've made with and without pendants just do not stay straight and have a tendency to slide one way or the other. What is the key to keeping them in place and keeping the middle of the necklace where it should be?
Taking into consideration the weight and sizes of different beads used in your design is a good first step in solving this common problem with necklaces. A sure way to keep a pendant centered is to make sure that the pendant is the heaviest bead in the necklace. A necklace without a pendant should be balanced by making sure the same number of beads (of each type of bead used) are used on each side of the necklace.