Avoid very rich soil, or your will get lots of vines and no potatoes. I rototill the area as deep as I can, shovel dirt off paths into ridges, then till the paths again. It helps to water the young plants in, but don't worry if they wilt for a short time after transplanting. Control weeds and conserve soil moisture during the long growing season by mulching. Soon you will be unable to see the mulch for the luxurious vines.
Insect pests are a little problem, but deer can devastate the crop.
An electric fence or a deer repellent such as hinder can help. If all else fails, tie a dog in the garden at night. When the first frost threatens, dig the sweet potatoes carefully with a spade or fork and hands. Some sweet potatoes will grow in unexpected places where the vines sent down new roots. Cure the potatoes in a warm, dry place for 5 days to prepare for winter storage, or can them.