To make a creamy cacio e pepe sauce, it is important to use the right type of cheese. Pecorino Romano is the traditional cheese used in the dish and is known for its sharp, salty flavor. It is also important to use freshly grated cheese, as pre-grated cheese can be dry and clumpy. Another tip is to reserve some of the pasta water and use it to help create a creamy sauce. Finally, it is important to constantly stir the pasta and sauce together to ensure that the cheese melts evenly and the sauce is creamy.