One of the finest ways to make turkey soft and juicy is to marinate it when cooking. Some recipes call for marinating overnight, but two to four hours would suffice. If you leave the turkey out for longer, the meat will turn tough and stringy. Turkey can also be marinated for as little as two hours and still be excellent. Finding a balance of tart acids, rich oil, and sugar is the secret to successful marinating. The sour acids help tenderize the meat by breaking up harder muscle fibers.