Here is the basic gist of what it takes to join the Craftsmen guild, straight from Garret:
To become a member of the guild people need to have satisfied the following:
guild. If that person isn't the GL, or another authorized person, whoever they contact needs to verify that they can indeed RP at an acceptible level.
ready. This can of course be spread over a variety of characters.
After all that if everything is up to par, they can join, base rank is Petitioner. If they have found a master already to apprentice to, then they can join as an Apprentice.
Note that at the moment, people can contact Garret by mudmail.
For a speedier response time one should contact one of the Guild Immortals. They are responsible for adjunct guild administration duties, and can handle induction and contacting of Garret or another person who does teaching. A list of Immortals responsible for Guild Administration can be found under help duties.