To help keep your doll in good shape, carry it supporting the body.  
The dolls are made of either light colored or orange fabric so they show up well in photographs.  Use a permanent marker to indicate the front and back of the doll.  Add a face if desired.
Great tip:  One investigator dresses her doll in a white onesie and stocking hat.  She then tucks in weights as needed.  This can also help keep the dolls clean.

Water repellents:  Some investigators have used spray-on water repellents, such as Kiwi Heavy Duty Water Repellent on the dolls for protection from water and stains.  

Do not carry a doll by the arm or leg as damage may occur due to the weight putting stress on the seams and fabric.