Q: memory is full

I have an iPad 2 and have recently signed up to use the iCloud.  But now I keep getting messages from the iCloud telling me that the memory is maxed out.  As far as I know, I only use it for photostreaming which I thought didn't count towards the minutes.  I even went through the settings and made sure the iCloud was off for all the apps except iPhoto and iCalendar.  What do I do inorder to clear the memory on my iCloud so I stop getting that memory maxed out message?