Artisan is the highest crafting badge you can receive. To become one, start with your crafting quest in Wizard City (you can get the quest from Eudora Tangletree in Olde Town) and continue along the crafting storyline all the way up to Celestia. The last quests are very difficult, so good luck!
By the way, there are two artisan badges: Master Artisan (Dragonspyre) and Grandmaster Artisan (Celestia). Hope this helps.
