If you are accessing certain websites very often with your Android powered Samsung Galaxy S2, I suggest you to add a bookmark shortcut to your phones Home screen.
You can set notifications to find out when your collaborators have modified your spreadsheets, and learn what sheets or cells they've modified. You can also choose how often you'd like to be notified.
If you are more of a visual person and would like to organize your folders and files using different colors, than check it out how to use color labels in Mac OS X.