+1 to everything that csdf has said. Spot on ^

Also, try to get a landing card on your inbound flight and fill it in before you land. They are scattered around the arrivals hall, but you don't want to waste time filling it out or trying to do this standing up. You'll need a pen for this

Follow the apparently experienced and relaxed westerners. And if in doubt, act clueless but respectful, and smile a lot. The Arabic for 'thank you' is 'shukran'

If you are sent to the first-time entry line, you may be taken right to the front, with several dozen/hundred Asian workers behind you. It may not be right, but it's just the way it is ...

How are you getting into town ? If your host or hotel is sending a car, make sure you have a number to call if you're delayed in immigration. This also means you can politely ignore the touts. You shouldn't expect to pay more than SAR100 to a regular driver, or SAR150 for a hotel car.