How should I charge my iphone 5 on its first charge?

I heard that I should charge it for at least 12 hours before I use it. And then I heard that I should just charge it after I drain the battery.

What should I do?

Added (1). If my iphone is already at 100% charged when I first take it out of the box, should I still charge it?

It doesn't really matter.
Personally, I would fully charge it before using it.

Erm… I think if its fully charged… You don't need to charge itt…
Unless its like out of battery.
Okay bye!

Charge ur mobile until you see fully charged message… Then switch off the charger for a minute and switch it on back again, it will start to charge again. Now after reaching 100%, remove the charger and use ur mobile like normal and full drain it until the mobile shuts down on its on… Then onwards charge normally!

Gone are the days when you need to fully charge your mobile phone when you first get it. Modern batteries don't need essential first charge. If you use it as normal you will notice that the operating period gets better over the first few charges but you really need to run it down fully before you charge it for the first time

Just throw it away and get Samsung Galaxy Note 2(or the S3) it's way better than the iphone5