remove plugs, spin engine over with injectors disabled to try and remove any fuel that may be lying in there, hold throttle open so plenty of air.

At the same time, spin the engine over ( plug on lead and grounded, but not in engine just so it spins faster ) and hook up a timing light to cyl1 and see if you are getting spark that would be at a time sensible enough to actually allow starting.

I assume the engine can get air ok ?

Compression test ?

Easy Start ?