1. Get goblin engineering in Tanaris.
2. Stand by the goblin engineer, and destroy your card.
3. Talk to the trainer you are standing by and accept his "quest".
4. Complete "quest" and recieve your new card.
5. Return to step 2.
It costs 2g ever time you reach step 3-4. You can repeat the quest safely 10 times a day (took me about 2 minutes), though beyond that I do not know. You will have to wait 24hrs to recieve a giftbox in the mail with a smallish percent chance to get the pattern.
For those of you tht are a bit confused about this whole renewing business here it is:
At lvl 200 engineering you have a choice: to spec Goblin engineering(bombs and the like) or Gnomish Engineering(whacky trinkets that'll prolly blow you up).
After completing the quest for either you receive a membership card Goblin/Gnomish, this card allows you to buy special schematics that you would not be able to buy otherwise.
After receiving/renewing your card you receive a care package in the mail with special Goblin/Gnomish schematics such as Li'l Smoky(Gnomish) or this Pet Bombling(Goblin).
pic i found:
Sorry if its a repost just found this today and not really seen anyone with one of these
Enjoy and flame on :P