This isn't a glamorous or creative tip, but it's a very practical one that many people overlook when entertaining. Do a sweep of your bathroom the day of your party to stash anything you wouldn't want your guests to see. Check your medicine cabinet, under your sink and empty the bathroom garbage right before guests arrive. I don't think most people purposely snoop in your bathroom, but looking for the spare roll of toilet paper or a feminine product may lead to an embarrassing discovery. Your friends would likely rather not find something so personal, so do them a favor and stash it in the back of your linen closet or another discreet place.
If you're curious, that is my bathroom pictured above.