Crafting for me was basically just doing the efficient leves and the Crystarium quests. BSM and ARM synergize so f'n well with leveling each other, it's almost criminal sometimes. Spam ingots on one, use to make leves for other. Swap each tier. It makes really good use of the crafter xp scrolls and you level two at once. Culinarian is another one that always seems like "Oh hi, just make this one thing -forever- ?" a lot of the time. Some like 74 leve is good all the way to max (I may be misremembering) just because it's easy to HQ, you can do triples, and the mats are a joke to farm up. Seems there is always one for Culinarian that you can just ride forever.
edit - Of course, I always assume people max gatherers probably first, while they farm up all the mats. Spending leves on gatherers is doing it wrong; those are your hardcore grind centric classes where you always want a gatherer xp scroll going. -Especially- fishing. Then you use all the shit you spam gathered to level all the crafters.