Doing lots and lots of Event Map #4. It helps that I don't have to do the re-issues. Only thing I spend LC on are the Rainbow and Gold Skillblooms, then I start saving again till I have 1,000 for when the store restocks. Only times I use LC for anything else, is when I manage to gather more than ~1,200 LC before the store restocks. And even then I'm reluctant, simply because some events have been stingy on LC drops.
There's usually a chest that gives 5-6 LC on the last event map, but it's the extra LC's from surprise gold chests that seem common on some events, but almost non-existent during others. Current event seems about avarage for me though. Not exceptional, but it's enough to reach my monthly target.