Unless you grow your own grapes, in which case you can simply pick tender young leaves, you can make do with commercially grown and packaged vine leaves that you can find in delicatessens and most grocery stores. Laid flat in brine, or bottled, all they need is a good rinse to wash away the brine. Older, fresh leaves do perfectly well, but you need to simmer them for up to 15 minutes.
Fillings vary, but the basic ingredients are a mixture of rice, pine nuts, currants, cinnamon, and herbs that include parsley, dill or mint, with or without ground lamb or beef. Onion is an optional extra, as the aim of creating a filling is to balance and complement the delicate flavor of the leaf rather than overwhelm it with distinctive tastes such as garlic, tomato and stronger herbs.
Rather than buying commercially packaged vine leaves, prepare your own and have them always on standby for up to a year. They're best picked young, but you can cut out the tough veins and stalk of older leaves, and you should avoid using chemically sprayed leaves. Freezing, canning or storing in airtight jars in a brine solution preserves leaves perfectly well for up to a year, and you can preserve them by weight or layers.
Although dolmades are often included on a plate of hors d'oeuvres, or pre-dinner aperitifs in a restaurant, the usual presentation is in small dishes that are offered as a meze, plural "mezethes," for people to nibble while having drinks and conversation. Everyone at a table shares a dish of each meze in much the same way as people share chips or peanuts, and each dish contains something different, such as peeled radishes, olive paste with bread, or olives on their own.