If I'm approaching a junction where a vehicle is waiting to pull into my path, I watch their front wheels. I find this often gives an earlier indication that the driver is about to move than their head or eye movements, as you can see the change in weight distribution when a driver prepares to move away.
As a motorcyclist this is exactly what I do too. Its impressive how often people will telegraph a turn before they ever really turn.
Managed to not get into many an accident by watching the heads and front wheels of cars. Also, look for signs of them being on a phone, if so remove yourself from their area asap.
