Number of methods to keep the turkey moist;
a) Brine it, place it in a bucket of water with salt, pepper and various herbs and spices this will help keep everything moist and will introduce some flavours into the meat, very popular in the US.
b) Roast the turkey upside down so the fat and juices run from the dark meat (where all the flavour is) through the breast meat.
c) Bare minimum would be to cover the breast of the turkey with rashers of streaky bacon, also cover this with foil until halfway through cooking.