What to do if your iphone isn't charging?

I have the iphone 4S, and i always charge it. Last night, i charged it, (and it said it was charging) and i woke up and it didn't charge at all. So when i got home from school, i charged it again (and it still said it was charging) and it didn't charge… In fact, the battery percentage went down. I reset my settings, and restarted the iphone and nothing worked. And i blew on the charger. What do i do?

You could go to a apple store and buy a new one or ask if they can fix or replace it

First try a new charger and cable (but save the receipt so you can return it if that doesn't help). If they don't help, you need to replace the battery. Find a local phone repair place; there was a guy near me who put a new battery in my 4S for $30.

Get a warranty.