For arrivals, the priority lanes are the first few on the left side. You'll notice significantly less people stacked up, maybe some passengers in wheelchairs and some immigration officers walking around eyeballing passengers headed into those lanes. Hopefully flashing your J-class VNA boarding pass to them does the trick. As for pre-booked transfers, the custom is for the drivers to be immediately outside the arrivals hall exit holding up an identifying placard (your name, company's name, hotel, etc).