Instructions
Study the subject of gold maker's marks and hallmarks by reading books such as William Chaffer's "Concise Hallmarks on Gold and Silver." Remember that many makers make gold and silver items and their marks may be the same for both metals.
Visit goldsmiths, jewelry stores, auctions and pawn shops to practice your skills in identifying makers' marks.
Keep a notebook detailing marks as you become familiar with them and to whom they pertain, since you cannot hope to remember them all. French marks, for example, are the most complex of all since they do not consist of any numbers, but instead employ animal symbols.
Research the assay office website for each European country in which you are interested. These contain researchable databases that will provide you valuable information and pictures of maker's marks and hallmarks.
Ask an expert in the field to mentor you as you learn to identify precious metal objects and their makers.
Seek expert advice from at least one expert prior to expending a large amount of money on a European gold item.