Unfortunately there is no way acquire leves faster, although you can hold up to 100 at a time. Once you complete the MSQ "In Pursuit of the Past" at 41 you unlock dailes from the beast tribes. The one's offered by the Ixal camp in the North Shroud are a great way to level crafting classes, although you are limited on how many you can do a day. Doing your grand company's delivery requests once a day can also get you a good amount of crafting exp (the list needed is under timers). While leves are in short supply I'd use those to level crafting and save leves for gathering if you want to work on both.