Well, you should probably check all your grounds and connections. You've checked for spark and still nothing? If so, the neutral safety switch has been known to cause no-start situations. Try starting it in park and in neutral. Not sure if it's the nss or the cps that could start in N vs P.
Could it be a fuel issue? Maybe your pump is shot, something along those lines. Look up fuel pressure tests in your manual or online.
Or a preliminary test: I think you just pull the 4 bolts off the rail, wiggle the injectors loose without turning them too much. Then you would find something to catch the fuel spray with (*Fire extinguisher handy) and turn it over. Pretty sure all should spray at first.
If that's good: do your pressure test.
If that's bad: probably fuel pump.
Whenever you remove the injectors it's a good idea to replace the o-rings. Leaky fuel obviously a major fire hazard. O-ring kits are under 15 bucks- 2 rings per injector and one or more for the pressure regulator which you probably wouldn't need to mess with. My manual says to use the black/brown o-rings on specific ends of the injectors, but my kit came with all brown o-rings which is just fine. Use Vaseline on the rings to seat them. Helps you install without any damage and will get eaten away by fuel with no adverse effects.