The basic idea behind all the crafts is to transform cheap materials into something more valuable. However, none of the crafts are profitable until you gain a sufficient skill level. The skill levels are as follows:
Novice > Apprentice > Accomplished > Adept > Talented > Skilled > Expert > Master > Grandmaster > Champion > Legendary
In order to succeed beyond the accomplished level in a craft, one must specialize in the craft.
Crafts
Craft Blocks
You can do all Gathering Crafts up to Legendary.
You can do all Manufacturing Crafts until Accomplished, Then specilize in one for Legendary, Food prep can be done to Legendary regardless.
You can only be Legendary in 1 craft of the following: Smithing,Carpentry,Tailoring, and Jewler.
You can be Legendary in Chef regardless of other crafts.
You can only become Legendary in either Scribe or Alchemy. And you have to be a spell caster to do either of those crafts.