Checking fuel and spark: Have a buddy spray starter fluide (not charcoal, engine starter fluid) while you crank the engine.
If it catches and dies, spark is good, and problem is fuel. If it doesn't catch, then its and/or spark, fuel.
Checking spark: disconnect a plug wire, while a buddy cranks, move the end of the wire closer to teh plug and see if a spark arcs across, might need to be in a dark place