There is a really simple way of freeing up a ton of space that no one discusses because it is hidden yet so obvious. Your text messages and iMessages and all the photos and videos sent and received in them are hogging a ton of space. I deleted all mine and went from using 4.9 GB of space to 232 MB.
Go to you messages app and delete as many text messages and iMessages as possible. I deleted them all, but if you want some, delete as many as you can. At the moment, with ios7 there is no way to delete all at once, so you have to manually delete each thread. Just hit edit at the top and starts deleting.
Then go back into your icloud settings and see how big the backup will be. You'll be shocked. Another additional step is to delete your backup and save a new one immediately. That's just me though because I like to start from scratch. Just make sure you are connected to wifi and can plug in while doing this.
Let me know how it goes?