Lore Keepers

Lore Keepers stock techniques by the hundreds!  If you need a specific technique, you can bet that the Lore Keeper has it.  The only problem is that Lore Keepers only accept Imperial Lore Tokens as payment.  Certain Lore Keepers only accept certain tokens too, as they come in different sizes, such as beginner and journeyman.  You can find tokens on monsters, with bigger monsters dropping more valuable ones.  Formulae can get awfully expensive, so horde them!  Many crafting trainers will also give you tasks for tokens.  These tasks can be simple, such as gathering 50 of some unrefined resource, or it can be more complicated, such as crafting a set number of items.  

Another option to consider is the random formula generator.  Instead of trading for a formula, you can give the Lore Keeper one token.  He will then randomly select a formula for you that is appropriate to your craft skills.  If you are willing to risk it, this method can really pay off!

You can find lorekeepers, both beginner and journeyman, in Kirasanct (bottom floor), Sslanis, in the big building below the drop point, on the top floor of the Cleric building in Dalimond, and in Tazoon, inside a building just north of the shrine.  There is also a beginner keeper in Chiconis and a journeyman keeper in Dralk.

One thing to remember is that the lore keepers don't stock every form in the game.  The developers have been adding formulae as the game has progressed, but the journeyman lorekeeper especially does not have every formula you will want.  Despite this, you can get these forms through the random form generator feature.  Your other recourse is to kill monsters or find the form on a consigner!