MacBook charging question.

I received my new MacBook Air today and I couldn't see any charging instructions and the machine was already highly charged when delivered, so I have been using the laptop all evening and let it run out completely before plugging it in and allowing it to fully charge overnight. Does this seem like the right thing to do?

Also, when is it okay to recharge the laptop again? Do I have to use it to a low percentage before plugging it in, or can I use it to, say, 60% and then charge it again? I don't want to ruin my battery life! Thanks, guys.