With 3.0.2 released, new additions to many gathering professions have been added, and the most notable of these additions is that by leveling up skinning, every skill stepstone (75->150->225->300->375) you gain 3 extra critical rating as a passive stat from a buff called "Master of Anatomy", giving you an effective critical rating boost of 15 at the skill of 375. Now, what's pretty crazy about this is, skinning doesen't require you to be any particular level to get skill ups till 375!
You see where this is going? Yeah, the whole trick is just to level skinning up to 375 as a level19 twink! It is possible by getting summoned to Outland by a warlock and then skinning high level mobs that other people have killed and looted for you! Eventually you will reach the 375 cap and you can enjoy your free 15 critical rating which equals to 5.07% crit chance at level19!
Have fun getting the edge over other twinks!
Edit: The whole point of this exploit is that YOU CAN get 375 skinning as level19, it's most likely a bug! Other professions won't allow you to do that. Don't claim anything else since this is the case, this does work.
Edit2: Here's a link to WoWWiki article about skinning, it should prove that I'm saying the truth and that this actually works!
http://www.wowwiki.com/Skinning
Caption of the article: ""Skinning does not have any character level requirements in order to learn the next skill proficiency level."