Leveling your crafting skill is very painless in aion kina when compared to games like WoW, Darkfall, WAR, or any other MMO that comes to mind. There are 2 ways you can level skill in Aion.

1) You gather materials, craft items, accept the waste of your failed items, and get skill for successes, and sell your items you made-whether to a vendor or players.

2) You obtain a work order from the trainer of your skill, the governments of aion kina give you items, you craft them for them, get skill for making these items, and give back the finished product.

The second one is unheard of to me at least, and is a very nice way to level your skills without having to go back to all the low level areas to get materials if you want to level a skill at max level. There is one downfall however; the government expects you to bring your own tools to create things for them. For example, at skill level 1 we can make baked apples for the governments use. They give you apples, you use their oven, and you're done. But at level 10, we need to make salted trout to get skill faster. They give you the trout, but you need to buy salt to cook the fish. This is how they keep people from simply leveling an entire skill tree for free.

When using one of these types of crafting, you either get your own materials and tools, then keep the stuff you make - or you can use someone else's materials with your tools, then just get skill(plus a random item). This is a trade-off. You get only skill and lose money if you skill off the government, as opposed to taking up time and materials to gain money and skill if you farm your own materials. If you farm your own materials, you are more likely to find rarer items as you wander. But, the work orders have the little prop of getting a random item for each turn-in pertaining to the skill level(1p, 10p, 20p, etc) and type of item that you just turned in(Handcrafting, Alchemy, Cooking, etc). This means you can get a tool to use, a material to use, or a new recipe for the craft you are doing quests for.

To sum up how to choose to level your crafting:

if you easily find materials but don't want to get gold - level by crafting your own items. good for the slow leveler that loves to explore and have fun while leveling
if you easily get gold but don't want to go out and get materials - level by working for Aion's ruling body. good for the power leveler who wants to get as high of a number next to his little picture as possible before worrying about making things

Obviously the higher level you are, the more money you will make. Therefore; it will be easiest to level by government work if you stay at the crafting level most closely related to your actual level, since the tools/materials you need to buy will become progressively more expensive.