There is only 2 things you need to know about crafting.
Mats you farm yourself are NOT free, as you could otherwise have sold them for money, that money is their value.
Get mats as cheap as possible, buy-shops, bulk deals with people. Whatever it takes to shave a few adena off per item
Crafting shots is a nearly guaranteed profit, they don't vary much in price.
crafting gear is a luck game more than anything, don't spend everything you have to craft an item. If you can't afford a failure.