This was driving me insane too. I love my iphone but this is the one flaw. I tried all the "maximizing battery life" suggestions, and it helped slightly.
I have one suggestions: buy an iphone battery case. I bought one off ebay for $29.99 and it is amazing. Nearly doubles the battery and is way nicer than the one at Apple (not to mention 1/4 of the price). The item number is 200795419418 on eBay in case you are interested.
Hope That Helped!!