What uses up my data?

[<3]

I have the iphone4 and i try to use wi-fi as much as possible. I always try to use the internet and games when there is wifi, but recently my usage went from 62/300 to 158/300 within a day!
I had games like metal storm, words with friends and draw something but i deleted because i thought it was the reason why.

i had city story but it pissed me of so yeah oh and ninja fishing

sometimes my wifi at homes disconnects when i don't realize but i always check so it reconnects.

i use tango and facetime alot too..and i have a twitter app..

So any ideas why it used so much and how i can stop from using so much?
thankkks

[Sam]

Things that use up your data:
Surfing web pages
Using iMessage
Sending pictures/videos through SMS (what you'd normally use) or iMessage
Words with Friends
Draw Something
City Story
Ninja Fishing
Any games with "friends" or GameCenter
Twitter
Facebook
Just leaving your data on!

A lot of apps use data discreetly, you just have to be aware. For most games, I DON'T allow them to send me push notifications because that sometimes uses data.
I usually turn my data off by going to Settings - General - Network - and turning 3G and Cellular data off.