If your babywearing choice of the moment or day is a ring sling or wrap, do your back and shoulders a favor and fan the fabric out over the whole of your shoulder and across your back. Be sure the fabric is laying flat and wide, with no twists. This will help distribute the weight and keep the fabric from riding up into the crook of your neck.
The more comfortable you are with your sling on, the longer and more happily you can wear your baby.
Your body and your baby will thank you for it.