Best sequence to level up crafting jobs?

[Roth_Trailfinder]

Lvl 40 drg here. Have not started crafting at all. Should I start now or wait till I get to 50 ad drg? If so' what's the first to start at?

Start whenever you want.

My advice :
Take all crafts up at the same time, in discrete chunks. 1-15. 15-20. 20-30. 30-40. 50-60. (Or whatever sized chunks you want to use, that was just the chunk ranges I used.)
With two exceptions, start each chunk off with Weaver, and then Goldsmith. This is for the crafting gear you will want (easiest way to get HQ crafting gear for yourself is to make it yourself). Weaver covers clothes, Goldmsith covers jewelry. The two exceptions are the 30-40 chunk, and the 40-50 chunk. For the 30-40 chunk, start with Culinarian, then do Weaver and Goldsmith. For the 40-50 chunk, start with Carpenter, then Weaver.

After the first 2-3 crafting classes in each chunk, do them in whatever order you wish.

As for how to do them, start with the Crafting Log. Do all the Crafting Log recipes within the chunk you are working on (don't hit the 16-20 recipes when working on only hitting 15, for example) and if they do not suffice to bring you to the stopping point, then and only then use Leves to get the experience to hit the desired stopping point.

For the final run to 50, however, you may just want to do a bunch of Leves.