8. App History
Just like your browser has a history, so do many apps. From Google Maps to Urban Spoon, apps try to be helpful and save prior information. Just because your history is erased from your browser doesn't mean she can't see that you've been to a strange apartment or the bar across town four times this week. If she wants to blow up your spot, there's an app for that. Don't just cover your tracks once: cover them a few times over.