Instructions
Research all the types of cards created and available. Availability is key due to the lack of production in the West. Sailor Moon fan websites may be the best source of information on where to find them.
Look for places where you can buy the cards. Online stores, auction sites, anime conventions and trading card shows may be among your best sources, but locating fan websites where fans may trade is even better.
Decide how to preserve your cards, as all trading cards can wear easily. There's pretty much two basic types of protective sleeves--individual ones or pages of sleeves kept in a notebook.
Determine how to store the cards. Individual sleeves may require boxes or drawers for safe storage, while the pages can be kept in a book. Hanging them on the wall can also work - just don't damage the cards in doing so.