Got my first Mac. Questions regarding battery health.

Hi guys, I've just bought my very first Apple computer (not counting my iPad 2). I bought an 11" 2013 Air which should be perfect for university work. My question is this: How should I go about charging it? I want to keep the battery life as healthy as it can be so should I let it drop to a particular percentage before charging it? Is it ok to keep it plugged in? The usual questions, really, but as it cost me a lot as a non-earning student I'd really like to keep it in excellent conditions.

Thanks in advance.

P.S. If anyone has any other valuable information for a first time Mac user feel free to comment. I've only ever used Windows and Android with iOS only on my iPad. Thanks.