The only patterns you 'get' are a few basic ones when you pick Tailoring as your profession. After that you have to pay trainers to teach you others, as well as the ones that drop from mobs and in chests.
Some of the more common patterns are available at all traiiners, but as you get more experienced, certain patterns can only be found at certain trainers - for instance a lady in the basement of The Slaughtered Lamb inn in SW for Alliance, and Timothy Worthington in Theramore (also Alliance).
When skilling up Tailoring, some patterns are more efficent than others. I've recommended it in the past, I still recommend it, Lootables is a great guide if you are looking to figure out which is the most efficient recipe to use for skill-ups -
http://www.lootables.com/?guide=Tailoring
Thranathiril