Level all DoH at once so there's some variety.
Don't craft for too long at one sitting. Do your GC turn ins maybe a handful of leves and stop.
Sell your stuff on the mb and watch the gil roll in. This provides me no end of glee.

eta: Have a crafting party and hang out with your friends. A while back, a bunch of us sat on the ropes in MD and crafted. We've also had a gathering/crafting party outside Quarrymill. It's fun just to chat and be silly.