How can I preserve the battery cycles on my MacBook Air?
Don't stress about it so much.

A Battery cycle refers to, more or less, one mostly full discharge and recharge. Typically, your battery should be rated for somewhere in the neighborhood of 1000 cycles. Eventually, the battery just won't hold a charge for as long as it did when it was new, but that's why batteries are easily and affordably replaceable. It's a consumable part. If it dies prematurely (which is the only thing you should really need to pay attention to cycles for), then it's covered under your warranty. The 'Battery Cycles' indicator is mainly there so that you can diagnose this. If, in a years time, your laptop's battery only lasts half as long as it did when it was new, but you've only used say, 400 cycles, well, that's not performing up to spec, and it should be covered under your warranty. If you've used 1500 cycles (doing that in a year would be some pretty heavy and impressive use though, I've gotta say), well, that's to be expected. You used your battery a lot, and it wore out.

Use your laptop as normal. Battery cycles are not a scarce and precious resource to be hoarded. 12 cycles in about a week and a half sounds pretty normal for a new laptop being used heavily to me. That's about, what? 6 hours/day unconnected to a power source? If you're using it on the go, that's a perfectly reasonable amount of consumption.