Quartermasters

Quartermasters are probably your best bet to get techniques to make your crafting even better.  Quartermasters are found in several major cities and each sell different techniques.  Unlike other vendors, Quartermasters ONLY accept Imperial Bounty Markers as payment, valuing each marker for one copper coin.  Each technique will cost you several bounty markers, so horde those things!  Also, bear in mind that there are several techs that only appear as monster loot!

Quartermasters also offer quests to earn bounty markers.  These quests are very simple, such as gathering 50 processed tier I resources.  The reward is experience in both your adventure and crafting class, some copper, and a marker.  Since you don't need to craft the materials to complete the quest, you can carry several hundred bricks, bars, orbs, etc, to the quartermaster and get a few markers in one trip.

Dalimond - Spellcrafting Techniques

Tazoon South - Adventure and Socket Techniques

Mahagra - More Adventure Techniques, including attribute techs

Aughundell - Craft Techniques

New Rachival - More Craft Techniques (those not found in Aug.)