Before you hit the starter, make sure the fuel filter is full of fuel. The key cycled several times works. The quickest and easiest way to prime the PD injector is to remove the glow plugs and run the starter. The engine will spin faster and the fuel will come up quicker. And you can see the proof for fueling.
Run the starter in 10 second intervals, watching under the hood for the mist coming up from each injector hole. Usually, it's one-at-a-time, an injector will start to mist fuel out of the gp hole, then two, three... and when the fourth one shows fuel, insert the gp's and the engine should start very quickly.