A great place for jumpseat etiquette questions is jumpseatinfo.org. Plus there's a TON of related threads here on APC. It's just a search away. One thing I will add is always respect the jumpseat process and captain's authority. Never let a rude, hurried gate agent or FA try and pressure you to sit down without talking to the captain. FA's do this a lot and it goes to show that many of them don't follow the process or show the same professional courtesy when they're getting a free ride.