Expertise

If you wish to take the expertise route when crafting you simply do so by crafting with new materials in attempts to create new items and gain techniques through understanding. Below is an explanation of Expertise from Thad and the required amount of techniqures required to level expertise.

Expertise is a skill rooted in application and experience. The key to
advancing your Expertise is to craft persistently, taking care to seek
out new ideas and experiences to learn from.

Whenever you craft an item, especially one that is new to you, there is
a chance that you will gain a Technique Point in Expertise. These
Expertise Techs represent the newfound skill and understanding that you
have acquired. Note that gaining a Tech prevents further Tech gain in
any category for 18 hours.

You may see a list of the Expertise Techs you have acquired with the
'quests action, crafting' command. Likewise, any Expertise levels that
you gain will be permanently recorded in your quest log and can be
viewed with the 'quests completed, crafting' command. Each successive
level of Expertise requires a certain number of Techs, as follows (note
that Expertise Techs and Artistry Techs are not interchangeable):

[ Expertise level ] > Techs required

[ 1 ] > 0 [ 5 ] > 50 [ 9 ] > 110
[ 2 ] > 8 [ 6 ] > 65 [ 10 ] > 125
[ 3 ] > 20 [ 7 ] > 80 [ 11 ] > 140
[ 4 ] > 35 [ 8 ] > 95 [ 12 ] > 155