New 'Mastery' Options: After your mastery Aion Gold experience bar fills up, you will gain a new title: Master Apprentice.
But more importantly, after gaining mastery you also gain a new option, at the bottom of the crafting window you will see the "mastery option" you can use this to enhance the chance of making an improved product of what you are making. E.g. a cloth cloak with 10 armor becomes a stout cloth cloak 14armor +2might, or an umber dye becomes 3 umber dyes.
But you can only get this with a chance, the base is 5% after getting master but you can also use mastery items to enhance that chance by up to 44% also stacking that with an ancient steel tool that leads to a total 69% chance!
Shortcuts to all of this are available at Strategy Freaks - they offer a number of Lord of the Rings Online bots that level over night and provide outright Lord of the Rings Online cheats that basically get you ahead in an instant by using exploits.
When you gain a proficiency you automatically learn the default recipes at the new tier but you can also purchase some new recipes from the vendor for your trade (e.g. Novice Tailorer), or from the auction house.