Olive oil must always be extra virgin olive oil. More flavorful olive oil will be darker in color but many bottles are tinted to make it look darker. Parmesan is quite sweet. Grated nutmeg is always added to egg dishes and to some cheese dishes. You need to buy a whole nutmeg and a tiny grater for it.
Fresh nutmeg is always much better.
Northern Italian tomato sauces are flavored with basil. In the summer, this is fresh basil and in the winter it is dried basil. There are some exceptions. The salad of fresh tomatoes, mozzarella and basil, called Caprese Salad originated in Campagna which is southern Italy but it uses basil. Southern Italian tomato dishes and sauces, including pizza sauces, are always flavored with Oregano.